JP6535705B2 - Particle therapy equipment - Google Patents

Description

  The present invention relates to an accelerator and a particle beam irradiation apparatus, and more particularly to an accelerator and a particle beam irradiation apparatus suitable for application to treatment of cancer.

  The particle beam irradiation apparatus is roughly divided into a particle beam irradiation apparatus having a synchrotron as an accelerator (for example, see JP-A-2004-358237) and a particle beam irradiation apparatus having a cyclotron as an accelerator (for example, JP-A-2011-) 92424) is known.

  A particle beam irradiation apparatus having a synchrotron includes an ion source, a linear accelerator, a synchrotron, a beam transport system, a rotating gantry, and an irradiation apparatus. The synchrotron has an annular beam duct, and the beam duct is provided with a plurality of deflection electromagnets, a plurality of quadrupole electromagnets, a high frequency acceleration cavity, a high frequency application device for emission, and an output deflector. The ion source is connected to a linear accelerator, and the linear accelerator is connected to a synchrotron. A part of the beam transport system connected to the exit of the synchrotron is installed in the rotating gantry and communicated to the irradiation device installed in the rotating gantry.

  Ions (eg, positive ions or carbon ions) emitted from an ion source are accelerated by a linear accelerator. The ion beam generated by the linear accelerator is incident on the annular beam duct of the synchrotron. The ion beam circulating in the beam duct is accelerated to a predetermined energy in a high frequency accelerating cavity to which a high frequency voltage is applied. By applying a high frequency voltage from the high frequency application electrode of the high frequency application device for extraction to the ion beam which has circulated and reached the predetermined energy, the ion beam is emitted to the beam transport system through the extraction deflector. The ion beam is irradiated from the irradiation device to the affected part of the patient's cancer on the treatment table. The rotating gantry rotates the irradiation device so that the beam path of the irradiation device coincides with the irradiation direction of the ion beam to the affected area.

  When the affected area is divided into a plurality of layers in the irradiation direction of the ion beam, and the ion beam is scanned for each layer, the energy of the ion beam is changed to specify the layer to be reached. The energy of the ion beam is adjusted by controlling the high frequency voltage pattern applied to the high frequency accelerating cavity, the excitation pattern of the quadrupole electromagnet and the excitation pattern of the deflection electromagnet as described above. The scanning of the ion beam in the layer is controlled by adjusting the excitation current of the operating electromagnet provided in the irradiation apparatus.

  A particle beam irradiator having a cyclotron comprises an ion source, a cyclotron, a beam transport system, a rotating gantry and an irradiator. The cyclotron has a vacuum vessel composed of a pair of opposing iron cores having a circular cross section, a high frequency acceleration device and an extraction electromagnet. The beam transport system is in communication with the exit of the cyclotron where the extraction electromagnet is arranged. The beam transport system, the rotating gantry and the irradiator in a particle beam irradiator having a cyclotron are substantially the same as these structures in a particle irradiator having a synchrotron.

  In a particle beam irradiation apparatus having a cyclotron, ions (for example, positive ions or carbon ions) emitted from an ion source are incident on the center of the cross section of the core of the cyclotron and accelerated by a high frequency accelerator. The accelerated ion beam spirals from the center of the iron core toward the inner side surface of the return yoke and is emitted to the beam transport system by the extraction electromagnet provided at the periphery of the iron core. The emitted ion beam is irradiated from the irradiation apparatus to the affected part of the patient's cancer on the treatment table through the beam transport system.

  When the affected area is divided into a plurality of layers as described above using a particle beam irradiation apparatus having a cyclotron, and the ion beam is scanned for each layer, the beam is transmitted using a degrader provided in the beam transport system. Adjust the energy of the ion beam emitted to the transport system. The degrader adjusts the energy of the ion beam reduced by the degrader after passing through the degrader, that is, the energy of the ion beam irradiated to the affected area, by a single metal plate of different thickness or a combination of a plurality of metal plates. Usually, since the energy of the ion beam accelerated by the cyclotron is constant, the energy of the ion beam is usually raised by the cyclotron up to the maximum energy necessary for cancer treatment, and this energy is provided to the degrader It is attenuated by transmitting a certain metal plate and adjusted to a predetermined energy.

  Unexamined-Japanese-Patent No. 2014-160613 describes the cyclotron which can raise the extraction efficiency of an ion beam used for the particle beam irradiation apparatus. This cyclotron is formed on both sides of the orbit of the ion beam, and has a plurality of convex portions and a plurality of concave portions alternately arranged in the circumferential direction, and the hill region sandwiched by the convex portions and the concave portions The orbit of the ion beam in at least one valley area other than the valley area provided with a pair of magnetic poles forming a pinched valley area along its orbit, a de-electrode provided in the valley area, and a de-electrode The acceleration cavity is disposed on the outer peripheral side in the radial direction to accelerate the ion beam. In this cyclotron having an accelerating cavity other than the de-electrode for accelerating the ion beam, the amount of increase in energy per one turn of the ion beam is increased, the turn separation is increased, and the extraction efficiency of the ion beam is improved.

  JP-A-10-118204 divides a cancerous affected area into a plurality of layers from the patient's body surface in the irradiation direction of the ion beam, and scans a thin ion beam to a plurality of irradiation positions in each layer. A charged particle beam irradiation method of irradiating an ion beam is described. The movement of the ion beam to the next irradiation position in the layer is performed by controlling a scanning electromagnet provided in the irradiation apparatus. Also, transfer of the ion beam from the deep layer to the shallow layer is performed by changing the ion beam energy. As the energy of the ion beam increases, the later-described Bragg peak of the ion beam reaches a deeper position in the affected area. When a patient is irradiated with an ion beam, the dose distribution as shown in FIG. 3 of JP-A-10-118204 is shown in the depth direction from the patient's body surface, and the dose is maximized at the Bragg peak, Furthermore, the dose distribution sharply decreases at depths beyond the Bragg peak. In cancer treatment using an ion beam, the dose is maximized at the Bragg peak, and the property in which the dose sharply decreases at the depth beyond the Bragg peak is used.

  In the particle beam irradiation apparatus described in Japanese Patent No. 3472657, a circular accelerator for emitting an ion beam is attached to a rotating frame that rotates in a vertical direction, and a beam transport chamber for guiding the ion beam emitted from the accelerator to a treatment room is provided. It is done. The beam transport chamber is connected to the exit of the accelerator. The beam transport chamber extends in the radial direction of the accelerator and is bent horizontally to just above the treatment room and then bent downward. A field forming device is attached to the tip of the beam transport chamber. The treatment room is formed within the radiation envelope, and the patient to be irradiated with the ion beam is mounted on a treatment table placed in the treatment room. The sidewall of the radiation surround is placed between the accelerator and the treatment room. The ion beam emitted from the circular accelerator passes through the beam transport chamber and the irradiation field forming apparatus and is irradiated to the affected area of the patient on the treatment table. In order to change the direction of irradiation of the ion beam, the direction of the irradiation field forming device is changed by rotating the rotation frame to rotate the accelerator and pivoting the beam transport chamber and the irradiation field forming device around the rotation center of the accelerator. Ru.

JP 2004-358237 A JP, 2011-92424, A JP, 2014-160613, A JP 10-118204 A Patent No. 3472657 gazette JP, 2006-239403, A

  A particle beam irradiation apparatus using a synchrotron can generate a plurality of ion beams having different energies in the synchrotron, and can change the energy of the ion beam emitted from the synchrotron. However, since a plurality of deflection electromagnets and a plurality of quadrupole magnets are required, the synchrotron is difficult to miniaturize to a certain extent or more. In addition, in the synchrotron, the extraction of the ion beam becomes intermittent, and the extraction amount of the ion beam decreases.

  On the other hand, the cyclotron can continuously extract the ion beam, and the amount of extraction of the ion beam is large. However, the energy of the ion beam generated in the cyclotron is constant, and extraction of the ion beam whose energy is lower than the maximum energy is impossible. For this reason, when a low energy ion beam is required, as in the case of irradiating an ion beam to a certain layer in the affected area, the degrader provided in the beam transport system so that the ion beam reaches that layer It is necessary to adjust the energy of the ion beam. The use of a degrader for adjusting the energy of the ion beam causes problems such as an increase in beam size of the ion beam due to the degrader, a decrease in the number of ions transmitted through the metal plate of the degrader, and an increase in radioactive waste.

  For this reason, there is a demand for a proton therapy apparatus that can continuously realize extraction of ion beams having different energies and can improve the extraction efficiency of the ion beams.

  An object of the present invention is to provide an accelerator and a particle beam irradiation apparatus capable of efficiently emitting ion beams different in energy.

A particle beam therapy system according to the present invention for achieving the above object comprises an accelerator in which a charged particle beam is generated, a beam transport system which is a transport path of the charged particle beam, and the beam transported through the beam transport system. An accelerator configured to form an irradiation field with a charged particle beam, wherein the accelerator has an iron core, a coil and an accelerating electrode for controlling acceleration and trajectory of the charged particle beam, and the iron core A substantially disk-like beam orbiting area for orbiting and accelerating the charged particle beam is formed in the enclosed area, and ions for the beam orbiting area are located at positions different from the center position of the beam orbiting area. An ion source provided so as to have an incident point, and a path for taking out a charged particle beam after acceleration on the opposite side of the central position with respect to the incident point It is that wherein the base end of the over-time emission path is provided.

  Since the ion incident part is disposed at a position different from the center of gravity of the main coil in the radial direction, the distance between adjacent ones of the plurality of annular beam orbits formed around the ion incident part is the beam from the ion incident part It becomes wider at the region on the opposite side of the entrance of the beam exit path from the ion incident part than at the entrance side of the exit path. Therefore, the ion beam can be easily separated from the beam orbit in the region opposite to the entrance of the beam exit path where the distance between adjacent beam orbits becomes wider, and the beam orbits around each annular orbit It is possible to efficiently emit ion beams having different energies.

  It has a pair of iron cores installed facing each other and forming an isochronous magnetic field between them, and an accelerating electrode which accelerates the incident ions, and the ion incident portion to which the ions are incident is the center of the iron core The above purpose can also be achieved by disposing at different positions in the radial direction.

  Since the ion incident part is disposed at a position different from the center of the iron core in the radial direction, the distance between adjacent ones of the plurality of annular beam orbits formed around the ion incident part is the beam emission from the ion incident part It becomes wider at the region on the opposite side of the entrance of the beam outgoing path starting from the ion incident part than at the entrance side of the path. Therefore, the ion beam can be easily separated from the beam orbit in the region opposite to the entrance of the beam exit path where the distance between adjacent beam orbits becomes wider, and the beam orbits around each annular orbit It is possible to efficiently emit ion beams having different energies.

  An annular main coil, a magnetic pole forming an isochronous magnetic field, and a plurality of acceleration electrodes for accelerating ions, the plurality of acceleration electrodes being directed from the inner surface of the main coil toward the inside of the main coil Each tip of a portion of the plurality of accelerating electrodes, which is installed so as to extend, extends from the position of the inner surface of the main coil toward the direction away from the inner surface of the main coil from the position of the inner surface of the main coil The above purpose can also be achieved by disposing at different positions in the radial direction.

  The tips of the plurality of accelerating electrodes extending from the position of the inner surface of the main coil toward the direction away from the inner surface of the main coil in the main coil are at positions different from the center of gravity of the main coil in the radial direction As it is disposed, adjacent mutual spacings of the plurality of annular beam orbits formed around the position where the tip of each of the plurality of accelerating electrodes is disposed is the entrance of the beam outgoing path from the ion incident portion The region on the side opposite to the entrance of the beam exit path is wider than the region on the side of the ion incident part. Therefore, the ion beam can be easily separated from the beam orbit in the region opposite to the entrance of the beam exit path where the distance between adjacent beam orbits becomes wider, and the beam orbits around each annular orbit It is possible to efficiently emit ion beams having different energies.

  It has a pair of iron cores installed facing each other and forming a magnetic field between them, and an accelerating electrode for accelerating ions, wherein the iron core forms a plurality of projections, and the plurality of projections are the center of gravity of the iron core The above object can also be achieved by being formed on the iron core so as to extend from the outer periphery of the iron core to a position different from that in the radial direction.

  The plurality of convex portions are installed so as to extend from the outer periphery of the core toward a position different from the center of gravity of the core in the radial direction, so the respective center portions of the plurality of convex portions are arranged The distance between adjacent ring-shaped beam orbits formed around different positions in the radial direction is the beam starting from the ion incident portion rather than the region on the entrance side of the beam outgoing path from the ion incident portion It widens in the area opposite to the entrance of the exit path. For this reason, the ion beam can be easily separated from the beam orbit in the region opposite to the entrance of the beam exit path where the distance between adjacent beam orbits becomes wider, and the orbits of each annular beam orbit It is possible to efficiently emit ion beams having different energies.

  (A1) An ion incident portion for supplying ions from the ion source is disposed at a position different from the center of gravity or center axis of the main coil in the radial direction, and each of the pair of iron cores is around the ion incident portion A plurality of magnetic poles are formed extending radially from the ion incident portion, with the tip facing the ion incident portion, and further, a plurality of concave portions extending radially from the ion incident portion around the ion incident portion, A further preferable configuration will be described below in an accelerator in which magnetic poles and recesses are alternately arranged around the ion incident portion, and the main coil surrounds a plurality of magnetic poles and a plurality of recesses respectively disposed in an iron core.

(A2) Preferably, in (A1) above, in each of the pair of iron cores, each of both sides of a straight line connecting the entrance of the beam emission path and the central axis of the main coil in a plane perpendicular to the central axis of the main coil. In the region, the high frequency acceleration electrode is disposed between magnetic poles adjacent in the circumferential direction of the main coil among a plurality of magnetic poles respectively disposed on both sides of this straight line in a plane perpendicular to the central axis
The tip of the high frequency acceleration electrode faces the ion incident part, and the high frequency acceleration electrode has a bending point,
The entrance to the beam exit path, which is one of the recesses located between the adjacent magnetic poles in the circumferential direction of the main coil, from the bending point of the high frequency accelerating electrode to the end face of the high frequency accelerating electrode facing the main coil. And 180 degrees, it is desirable that it is bent toward the 1st crevice which exists on the opposite side.

  (A3) Preferably, in (A1) described above, the beam current measurement device disposed in the first recessed portion is configured such that a beam orbit is formed in a beam orbiting region formed between a pair of iron cores The beam current measuring unit disposed in the first recess and a moving device for moving the beam current measuring unit in the radial direction of the main coil in the track plane in a track plane perpendicular to the central axis of the coil; It is desirable to have a position detection device for detecting the position of the beam current measurement unit in the orbital plane.

  (A4) Preferably, in (A1) above, when the position of the beam orbit measured by the beam current measuring device disposed in the first recess is not present at a predetermined position, each is attached to the plurality of magnetic poles It is desirable to have a first control device (for example, a coil current control device) that controls the excitation current supplied to each of the trim coils.

  (B1) A further preferable configuration will be described below in an accelerator provided with a beam separating device for separating the ion beam from the beam orbit at a plurality of positions in the radial direction of the main coil.

  (B2) Preferably, in (B1) above, the accelerator is coupled to each other across a beam circling region in which a beam circling trajectory in which the ion beam is circled is formed, in a pair of iron cores and a pair of iron cores An ion incident portion provided with a main coil arranged respectively and a beam path which is an emission port of an ion beam penetrating the iron core and supplied with ions from an ion source and formed in a beam circulation region is a center of the main coil and Are preferably arranged at different positions in the radial direction.

  (B3) Preferably, in (B2) above, a plurality of magnetic poles and a plurality of recesses are formed in each of the pair of iron cores, and the magnetic poles and the recesses are alternately arranged to surround the ion incident portion, It is desirable that the deflection electromagnet device, which is a device, be disposed in one recess toward the ion incident part.

  (B4) Preferably, in (B3) above, the deflection electromagnet device is disposed in a first recess which is one of the recesses located 180 ° opposite to the entrance of the beam emission path with respect to the ion incident portion. It is desirable to be done.

  (B5) Preferably, in (B4) above, it is desirable that a moving device for moving the deflection electromagnet device is provided.

  (B6) Preferably, in (B3) above, the beam current measuring device disposed in the recess where the deflection electromagnet device is disposed has a beam orbit formed in a beam orbiting region formed between a pair of iron cores A beam current measuring unit disposed in the recess in the orbital plane perpendicular to the central axis of the main coil, and a moving device for moving the beam current measuring unit in the radial direction of the main coil in the orbital plane; It is desirable to have a position detection device for detecting the position in the orbital plane of the beam current measurement unit.

  (B7) In the particle beam irradiation apparatus provided with the above-mentioned accelerator of (B2) and the irradiation apparatus which outputs the said ion beam radiate | emitted from this accelerator, a further preferable structure is demonstrated below.

  (B8) Preferably, in the above (B7), a rotation device for rotating the irradiation device and rotation of the rotation device to set the beam axis of the irradiation device in the irradiation direction of the ion beam to the beam irradiation object In order to irradiate an ion beam having energy that reaches a first control device (for example, a rotation control device) and a layer among a plurality of layers divided in the irradiation direction, which is a target of beam irradiation, The moving device is controlled to position the pair of oppositely excited magnetic poles of the deflection electromagnet device on the beam orbit where the ion beam having the energy circulates, and the pair of magnetic poles to be excited by controlling the power supply. And a second controller (eg, a massless septum controller) for exciting the

  (C1) A plurality of annular beam orbits formed by a plurality of magnetic poles formed on each of a pair of iron cores, in which ion beams of different energy circulate respectively are focused at the entrance of the beam emission path Further preferred configurations of the accelerator are described below.

  (C2) In the above-mentioned (C1) accelerator, a plurality of annular beam orbits whose centers are decentered from each other are formed, and these annular beam orbits are beams between the ion incident portion and the entrance of the beam path. The eccentricity of the annular beam orbit, which is focused at the entrance of the exit path, is 180 ° opposite to the entrance of the beam path from the ion entrance, and is spaced from each other around the ion entrance It is desirable to be formed.

  (C3) In the above (C2) accelerator, an orbital concentric area is formed in which a plurality of concentric annular beam orbits centered on the ion incident part are formed, and the orbital eccentric area surrounds the orbital concentric area Is desirable.

  According to the present invention, it is possible to efficiently emit ion beams of different energy from the accelerator.

It is a block diagram of the particle beam irradiation apparatus of Example 1 which is one suitable Example of this invention. It is a perspective view of the accelerator used for the particle beam irradiation apparatus shown by FIG. It is a cross-sectional view (II-II sectional drawing of FIG.5 and FIG.6) of the accelerator shown by FIG. FIG. 3 is an enlarged view of the vicinity of the incidence electrode of the accelerator shown in FIG. 2; It is a V-V cross-sectional view of FIG. It is the VI-VI sectional view of FIG. FIG. 3 is a side view of the massless septum shown in FIG. 2; It is an arrow line view of the direction of each VIII-VIII of FIG. It is a detailed block diagram of the control system shown by FIG. FIG. 3 is an explanatory view showing trajectories, isochronal lines, and magnetic field distributions of a plurality of ion beams formed in the accelerator shown in FIG. 2; Is an explanatory view showing a change in the gap between the 3 and pole 8E intermediate plane along the isochronous lines IL ₁ shown in FIG. 10. It is an explanatory view showing a change in the gap between the 3 and pole 8E intermediate plane along the isochronous line IL ₂ shown in FIG. 10. It is an explanatory view showing a change in gap between the pole 8E intermediate plane along the Figures 3 and isochronous line IL ₃ shown in FIG. 10. It is a characteristic view showing the relation between the distance in the direction of movement of the ion beam and the magnetic field intensity when the energy of the ion beam is changed. It is a characteristic view showing the relation between the distance in the direction of movement of an ion beam when changing the energy of an ion beam, and n value. It is a characteristic view showing change of 1 time modulation wave, 2 time modulation wave, and 3 time modulation wave by kinetic energy of ion beam. It is a characteristic view showing change of each betatron frequency by the kinetic energy of ion beam in the horizontal direction and the perpendicular direction. FIG. 10 is a characteristic diagram showing the relationship between the distance in the traveling direction of the ion beam and the horizontal β function when the energy of the ion beam is changed. FIG. 10 is a characteristic diagram showing the relationship between the distance in the traveling direction of the ion beam and the vertical β function when the energy of the ion beam is changed. It is explanatory drawing which shows the amount of kicking of the ion beam to radiate | emit according to the kinetic energy of ion beam. It is a characteristic view showing the relationship between the distance in the direction of movement of the ion beam and the horizontal displacement of the ion beam as to the trajectory by which the ion beam kicked out by the massless septum reaches the extraction position. It is explanatory drawing which shows excitation of a pair of opposing magnetic pole of the massless septum shown by FIG. It is a flowchart which shows the procedure from injection of the ion to the accelerator in the particle beam irradiation method using the particle beam irradiation apparatus shown by FIG. 1 to extraction of the ion beam from an accelerator. It is explanatory drawing which shows the relationship between the position in the radial direction of a vacuum vessel, and the quantity (beam current) of an ion beam. It is explanatory drawing which shows the change of each state quantity in the accelerator of the particle beam irradiation apparatus in process of operation. It is a flowchart which shows the procedure of irradiation of the ion beam to the affected part of the patient in the particle beam irradiation method using the particle beam irradiation apparatus shown by FIG. It is explanatory drawing which shows the beam circulation orbit formed in the accelerator of the particle beam irradiation apparatus of Example 2 which is another preferable embodiment of this invention. It is a block diagram of the particle beam irradiation apparatus of Example 3 which is another preferable Example of this invention. It is a block diagram of the particle beam irradiation apparatus of Example 4 which is another preferable Example of this invention. FIG. 30 is a detailed cross-sectional view of the accelerator shown in FIG. It is a detailed block diagram of the control system shown by FIG. It is a flowchart which shows the procedure of irradiation of the ion beam to the affected part of the patient in the particle beam irradiation method using the particle beam irradiation apparatus shown by FIG. It is a block diagram of the particle beam irradiation apparatus of Example 5 which is another preferable Example of this invention. FIG. 34 is a detailed cross-sectional view of the accelerator shown in FIG. It is a flowchart which shows the procedure of irradiation of the ion beam to the affected part of the patient in the particle beam irradiation method using the particle beam irradiation apparatus shown by FIG.

It is a block diagram of the particle beam irradiation apparatus of Example 6 which is another preferable Example of this invention. It is a detailed cross-sectional view (BB sectional drawing of FIG. 38) of the accelerator shown by FIG. It is AA sectional drawing of FIG. FIG. 39 is an enlarged view of the vicinity of the massless septum shown in FIG. 38. FIG. 40 is a side view of the beam current measurement device shown in FIG. 39. It is an arrow line view of the direction of DD of FIG. It is a block diagram of the particle beam irradiation apparatus of Example 7 which is another preferable Example of this invention. FIG. 43 is a detailed cross-sectional view of the accelerator shown in FIG. 42. It is a cross-sectional view (G-G sectional drawing of FIG. 45 and FIG. 46) of the vacuum vessel vicinity of the particle beam irradiation apparatus of Example 8 which is another preferable Example of this invention. It is EE sectional drawing of FIG. It is FF sectional drawing of FIG. It is explanatory drawing which shows the other example of arrangement | positioning of a massless septum. It is a cross-sectional view of the particle beam irradiation apparatus of Example 9 which is another preferable embodiment of the present invention.

  The inventors conducted various studies to realize an accelerator capable of extracting an ion beam continuously like a cyclotron and extracting an ion beam different in energy like a synchrotron.

  The inventors first focused on increasing the distance between the beam orbits of the ion beam orbiting in the vacuum vessel of the cyclotron (the distance between the beam orbits in the radial direction of the vacuum vessel). Increasing the spacing of the beam orbits, ie, increasing the spacing between the beam orbits (turn separation), increases the diameter of the vacuum vessel and increases the size of the cyclotron. This is against the miniaturization of the accelerator. Also, in the conventional cyclotron, concentric circular beam orbits are drawn in the vacuum chamber, and it is difficult to secure turn separation with high energy, so it is difficult to efficiently emit ion beams of different energies. there were.

  In a cyclotron, a circular vacuum vessel is used, and an ion source is in communication with the center of the vacuum vessel so that ions are incident on the center of the vacuum vessel. The inventors move the ion source connected to the center of the vacuum vessel in the cyclotron to the side of the beam outlet formed in the vacuum vessel and connect it to the vacuum vessel and connect the ions from the ion source to the vacuum vessel. We considered entering the vacuum chamber at a position shifted to the beam outlet side rather than the center. As a result, the distance between the beam orbits formed in the vacuum chamber between the ion incident position where the ions are incident from the ion source and the beam outlet becomes close, and the opposite side to the beam outlet in the vacuum chamber 180 ° In contrast to the position between the ion incident position and the ion incident position, the space between the beam orbits formed in the vacuum chamber can be widened, contrary to the distance between the ion incident position and the beam extraction port.

  The inventors have created a new accelerator capable of efficiently emitting ion beams of different energies by applying such a concept of beam orbits.

  Each embodiment of the present invention to which the accelerator newly created by the inventors described above is applied will be described below with reference to the drawings.

  A particle beam irradiation apparatus according to a first embodiment which is a preferred embodiment of the present invention will be described below with reference to FIGS.

  The particle beam irradiation apparatus 1 of the present embodiment is disposed in a building (not shown) and installed on the floor of the building. The particle beam irradiation apparatus 1 includes an ion beam generator 2, a beam transport system 13, a rotating gantry 6, an irradiation apparatus 7 and a control system 65. The ion beam generator 2 includes an ion source 3 and an accelerator 4 to which the ion source 3 is connected. The accelerator 4 used in the present embodiment is a variable energy continuous wave accelerator.

  The beam transport system 13 has a beam path (beam duct) 48 which reaches the irradiation device 7, and a plurality of quadrupole electromagnets 46, deflection electromagnets 41, and the like are directed from the accelerator 4 to the irradiation device 7 in the beam path 48. A plurality of quadrupole electromagnets 47, deflection electromagnets 42, quadrupole electromagnets 49, 50, and deflection electromagnets 43, 44 are disposed in this order. A part of the beam path 48 of the beam transport system 13 is installed in the rotating gantry 6, and the deflection electromagnet 42, the quadrupole electromagnets 49, 50 and the deflection electromagnets 43, 44 are also installed in the rotation gantry 6. The beam path 48 is connected to a beam emission path 20 (see FIG. 2) formed in a take-off septum electromagnet 19 provided in the accelerator 4. The rotating gantry 6 is a rotating device that is rotated about the rotation axis 45 and causes the irradiation device 7 to pivot about the rotation axis 45.

  The irradiation device 7 includes two scanning electromagnets (ion beam scanning devices) 51 and 52, a beam position monitor 53, and a dose monitor 54. The scanning electromagnets 51 and 52, the beam position monitor 53 and the dose monitor 54 are disposed along the central axis of the irradiation device 7, that is, the beam axis. The scanning electromagnets 51 and 52, the beam position monitor 53 and the dose monitor 54 are disposed in the casing (not shown) of the irradiation device 7, and the beam position monitor 53 and the dose monitor 54 are disposed downstream of the scanning electromagnets 51 and 52 . The scanning electromagnet 51 deflects the ion beam in a plane perpendicular to the central axis of the irradiation apparatus 7 to scan in the y direction, and the scanning electromagnet 52 deflects the ion beam in the plane to x direction orthogonal to the y direction Scan. The irradiation device 7 is attached to the rotating gantry 6 and disposed downstream of the deflection electromagnet 44. A treatment table 55 on which the patient 56 lies is disposed to face the irradiation device 7.

  The control system 65 includes a central control unit 66, an accelerator / transport system control unit 69, a scan control unit 70, a rotation control unit 88, and a database 72. The central control unit 66 has a central processing unit (CPU) 67 and a memory 68 connected to the CPU 67. The accelerator / transport system controller 69, the scan controller 70, the rotation controller 88 and the database 72 are connected to the CPU 67. The charged particle beam irradiation system 1 has a treatment planning device 73, and the treatment planning device 73 is connected to the database 72.

  The control system 65 will be described in detail with reference to FIG. The accelerator / transport system controller 69 includes an incidence electrode controller 83, a beam current measuring unit controller 84, an electromagnet controller 85, a massless septum controller 86, a coil current controller 94, a high frequency voltage controller 99, and a memory 107. Contains. The scan control device 70 includes an ion beam confirmation device 87, an irradiation position control device 89, a dose determination device 91, a layer determination device 92, and a memory 70. The CPU 67 includes an incidence electrode control unit 83, a beam current measurement unit control unit 84, an electromagnet control unit 85, a massless septum control unit 86, a coil current control unit 94, a high frequency voltage control unit 99, a memory 107, and an ion beam confirmation unit 87. The irradiation position control device 89, the dose determination device 91, the layer determination device 92, and the memory 70 are connected. The irradiation position control unit 89 is connected to the incidence electrode control unit 83, the electromagnet control unit 85, and the massless septum control unit 86, and the dose determination unit 91 is connected to the incidence electrode control unit 83. The layer determination device 92 is connected to the irradiation position control device 89. The memory 107 is connected to each of the entrance electrode control unit 83, the beam current measurement unit control unit 84, the electromagnet control unit 85 and the massless septum control unit 86, and the memory 70 is an irradiation position control unit 89, a dose determination unit 91 and layers. It is connected to each of the determination devices 92.

  Next, the detailed configuration of the accelerator 4 will be described with reference to FIGS. 3, 4, 5 and 6. The accelerator 4 has a circular vacuum vessel 27 including circular iron cores 14A and 14B facing each other. The iron cores 14A and 14B are combined to form a vacuum vessel 27 and to form an outer shell of the accelerator 4 as described later. Iron core 14A includes return yoke 5A and magnetic poles 7A to 7F, and iron core 14B includes return yoke 5B and magnetic poles 7A to 7F. The specific configuration of each of the magnetic poles 7A to 7F will be described later. The return yoke 5A has a circular base portion 74A having a predetermined thickness and a cylindrical portion (for example, a cylindrical portion) 75A extending in a direction perpendicular to the one surface from one surface of the base portion 74A. The return yoke 5B has a base portion 74B. And a cylindrical portion (for example, a cylindrical portion) 75B extending in a direction perpendicular to one surface of the base portion 74B (see FIGS. 5 and 6). Since the base portion 74A seals one end of the cylindrical portion 75A, the other end of the return yoke 5A is open. Since the base portion 74B seals one end of the cylindrical portion 75B, the other end of the return yoke 5B is open. The contact surfaces of the cylindrical portion 75A and the cylindrical portion 75B, which are contact surfaces of the iron core 14A and the iron core 14B constituting the vacuum vessel 27, are sealed.

  The iron cores 14A and 14B, specifically, the return yokes 5A and 5B face each other with their open portions facing each other as shown in FIGS. 5 and 6, and the cylindrical portion 75A and the cylindrical portion 75B are opposed to each other. They are connected to each other in a state where they are made to constitute a vacuum vessel 27. In this embodiment, in order to set the vacuum vessel 27 on the floor of the above-mentioned building, the return yoke 5B is positioned at the lower side and installed on the floor, and the return yoke 5A is mounted on the return yoke 5B ( See Figure 6). In the present embodiment, the cylindrical portions 75A, 75B form the side walls of the return yokes 5A, 5B, respectively, and become the side walls of the vacuum vessel 27. The ion entrance tube 3A connected to the ion source 3 disposed outside the iron core 14A is attached to the base portion 74A of the return yoke 5A and penetrates the base portion 74A.

  The surface indicated by the alternate long and short dash line formed in the vacuum vessel 27 at the position where the return yoke 5A and the return yoke 5B are in contact is an intermediate plane (median plane) 77 (see FIGS. 5 and 6). Inside is a surface where the ion beam is accelerated and circulated. Further, on the intermediate surface 77, as described later, beam orbits around which ion beams having different energies orbit are formed. In practice, since the ion beam orbits with betatron oscillation in the direction perpendicular to the intermediate surface 77 (the central axis C of the vacuum chamber 27), the ion beam has a certain width in the direction perpendicular to the intermediate surface 77. The light beam is circulated in the beam circulation area 76 (see FIGS. 5 and 6). The central axis C of the vacuum vessel 27 is also the central axis of the iron cores 14A and 14B.

  The suction tube 26 is disposed on an extension of the central axis of the ion incidence tube 3A, penetrates the base portion 74B, and is attached to the base portion 74B. A vacuum pump 25 attached to the outer surface of the base portion 74B is connected to the suction pipe 26. The suction tube 26 opens in the beam circulation area 76.

  Furthermore, the accelerator 4 includes magnetic poles 7A, 7B, 7C, 7D, 7E and 7F, high frequency acceleration electrodes 9A, 9B, 9C and 9D, annular coils 11A and 11B, massless septum 12, beam current measurement unit 15, and incidence electrode 18 and the aforementioned septum electromagnet 19 for taking out.

  The annular coil (preferably, a circular coil) 11B is disposed along the inner surface of the cylindrical portion 75B inside the cylindrical portion 75B of the return yoke 5B (see FIGS. 3, 5 and 6). The two lead wires 22 connected to the annular coil 11 </ b> B penetrate the cylindrical portion 75 </ b> B and reach the outside of the vacuum vessel 27. Similar to the annular coil 11B, the annular coil 11A is disposed inside the cylindrical portion 75A of the return yoke 5A and along the inner surface of the cylindrical portion 75A (see FIGS. 5 and 6). Similarly to the annular coil 11B, two lead wires (not shown) are connected to the annular coil 11A, and these lead wires penetrate the cylindrical portion 75A and reach the outside of the vacuum vessel 27. The central axis C of the vacuum vessel 27 is the central axis of each of the annular coils 11A and 11B. The respective centers of gravity of the annular coils 11A and 11B are located on the central axis C. The annular coils 11A and 11B are annular main coils.

  A curved septum electromagnet 19 passes through the cylindrical portions 75A and 75B, and is attached to the cylindrical portion 75B of the return yoke 5B. One end of the septum electromagnet 19 located in the vacuum vessel 27 is located inside the annular coils 11A and 11B. The septum electromagnet 19 forms a beam emission path 20. One end of the septum electromagnet 19 and the inlet which is one end of the beam emission path 20 are located in the respective vacuum vessels 27 and located inside the annular coils 11A and 11B and near their inner surfaces. The septum electromagnet 19 is disposed between the annular coil 11A and the annular coil 11B in the central axis C direction of the vacuum vessel 27.

  The magnetic poles 7A, 7B, 7C, 7D, 7E and 7F are formed on the iron cores 14A and 14B, respectively. The magnetic poles 7A, 7B, 7C, 7D, 7E, and 7F formed on the iron core 14A project from the base portion 74A of the return yoke 5A in the direction in which the cylindrical portion 75A extends. Each of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F formed on the iron core 14B protrudes from the base portion 74B of the return yoke 5B in the direction in which the cylindrical portion 75B extends (see FIG. 6). The high frequency accelerating electrodes 9A, 9B, 9C and 9D are attached to the cylindrical portions 75A and 75B of the return yokes 5A and 5B respectively through the waveguides 10A to 10D. The magnetic poles 7A, 7B, 7C, 7D, 7E and 7F and the high frequency accelerating electrodes 9A, 9B, 9C and 9D provided in the return yoke 5B are disposed inside the annular coil 11B (see FIG. 3). The magnetic poles 7A, 7B, 7C, 7D, 7E and 7F provided on the return yoke 5A and the high frequency accelerating electrodes 9A, 9B, 9C and 9D are also similar to the magnetic pole and the high frequency accelerating electrode provided on the return yoke 5B. It is disposed inside the annular coil 11A.

  The detailed arrangement of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F and the high frequency accelerating electrodes 9A, 9B, 9C and 9D in the return yoke 5B will be described with reference to FIG. The shapes and arrangements of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F in the return yoke 5A are the same as those of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F in the return yoke 5B. The shape and the arrangement of the high frequency accelerating electrodes 9A, 9B, 9C and 9D in the return yoke 5A are symmetrical to the shape and the arrangement of the high frequency accelerating electrodes 9A, It is symmetrical with the shape and arrangement of each of 9B, 9C and 9D. Therefore, the description of the magnetic poles and the high frequency acceleration electrodes in the return yoke 5A will be omitted.

  The magnetic poles 7A, 7B, 7C, 7D, 7E and 7F formed on the base portion 74B of the return yoke 5B are convex portions protruding from the base portion 74B (see FIG. 6).

  In the return yoke 5B, the magnetic poles 7A to 7F and the recesses 29A to 29F are alternately arranged in the circumferential direction of the return yoke 5B. That is, a recess 29A (first recess) is formed between the magnetic pole 7A and the magnetic pole 7B, a recess 29B is formed between the magnetic pole 7B and the magnetic pole 7D, and a recess 29F is formed between the magnetic pole 7A and the magnetic pole 7C. 3, 4 and 6). Furthermore, in the return yoke 5B, a recess 29C is formed between the magnetic pole 7D and the magnetic pole 7F, a recess 29D (second recess) is formed between the magnetic pole 7F and the magnetic pole 7E, and a recess 29E is formed between the magnetic pole 7E and the magnetic pole 7C. Are formed (see FIGS. 3, 4 and 5). In the return yoke 5B, a recess 29G in which the annular coil 11B is disposed is formed between each of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F and the cylindrical portion 75B (see FIGS. 3 and 6). .

  The tip of the ion incident tube 3A is surrounded by the tips of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F formed on the base 74A of the return yoke 5A. An incidence electrode 18 is attached to the tip of the ion incidence tube 3A, and is disposed in the beam circulation area 76 across the intermediate surface 77. The tip of the ion entrance tube 3A is in communication with the beam circulation area 76. The ion injection port, which is an ion injection port formed at the tip of the ion injection pipe 3A, and the input electrode 18 are disposed on the alternate long and short dash line X connecting the central axes C of the annular coils 11A and 11B and the entrance of the beam emission path 20. It is disposed to be shifted from the central axis C of the annular coils 11A and 11B to the entrance side of the beam emission path 20. That is, the ion implantation port and the incidence electrode 18 are disposed at a position different from the central axis C, and are disposed at a position different from the centers of gravity of the annular coils 11A and 11B. The ion implantation port and the incidence electrode 18 are disposed at positions different from the central axis C of the iron cores 14A and 14B. The ion injection port is an ion injection port for injecting ions into the beam circulation area 76. Furthermore, the ion incident portion 109 (see FIG. 10) for receiving ions from the ion implantation port is a region formed inside the innermost beam orbit, specifically, a beam around the incident electrode 18 It is formed in the circulation area 76.

  The recess 29D (second recess) located between the entrance electrode 18 and the entrance of the beam exit path 20, and the entrance of the exit path of the beam 20 relative to the entrance of the exit path 18 with respect to the entrance electrode 18 The recessed portions 29A (first recessed portions) are arranged in a straight line along a dashed dotted line X.

  In the accelerator of this embodiment, a plurality of convex portions (magnetic poles) are formed on the opposing iron cores in order to make the magnetic field distribution along the beam circulation orbit strong and weak and obtain strong convergence. Hereinafter, in the accelerator of the present embodiment in which the ion incident point is provided at a position on the orbital plane different from the center of the iron core which is circular, a convex portion (magnetic pole) for obtaining a magnetic field distribution forming an eccentric beam orbit The shape will be described. The shape of the iron core and its convex portion (magnetic pole) suitable for forming an eccentric beam orbit is different depending on the mass, charge, etc. of the ion particles to be accelerated, and is not limited to the shape shown in the drawing. The magnetic pole shapes described in the drawings and the following are examples of the present invention applied to protons. The core of the iron core is on the central axis of the iron core.

  The magnetic poles 7A, 7B, 7C, 7D, 7E and 7F formed on the base portion 74A of the return yoke 5B have ion implantation openings, ie, positions of the incident electrodes 18 in the horizontal direction (direction perpendicular to the central axis C). Are arranged radially around the The width in the circumferential direction of the annular coil 11B of each of these magnetic poles decreases toward the incident electrode 18. The tips of the magnetic poles are pointed, and the pointed ends face the incident electrode 18. The width in the circumferential direction of the annular coil 11B of each of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F is the largest at the portion of each magnetic pole facing the annular coil 11B.

  The magnetic pole 7A is formed by bending points 24A and 24B formed on two opposing side surfaces, the magnetic pole 7B is formed at bending points 24C and 24D formed on two opposing side surfaces, and the magnetic pole 7C is opposed 2 They are bent at bending points 24E and 24F formed on the two side faces (see FIG. 4). Further, the magnetic pole 7D is formed at two opposing side surfaces at bending points 24G and 24H, the magnetic pole 7E is formed at two opposing side surfaces at bending points 24I and 24J, and the magnetic pole 7F is opposed to one another. They are respectively bent at bending points 24K and 24L formed on the two side surfaces (see FIG. 4).

  The portions of the magnetic poles 7A, 7B, 7C, 7D, 7E, and 7F between the respective bending points and the end face facing the annular coil 11B are bent toward the concave portion 29A. That is, the portion between the bending point of each of the magnetic poles 7A, 7C and 7E and the end face facing the annular coil 11B is bent toward the concave portion 29A in the direction in which the ion beam circulates. The portions between the respective bending points of the magnetic poles 7B, 7D and 7F and the end surface facing the annular coil 11B are bent toward the concave portion 29A in the direction opposite to the direction in which the ion beam circulates. The absolute values of the bending angles of the bent portions of the magnetic poles 7A and 7B are the same. The absolute values of the bending angles of the bent portions of the magnetic poles 7C and 7D are the same, and the absolute values of the bending angles of the bent portions of the magnetic poles 7E and 7F are the same. The absolute value of the bending angle of each magnetic pole increases in the order of the magnetic pole 7A, the magnetic pole 7C, and the magnetic pole 7E. The absolute value of the bending angle of the magnetic poles 7E and 7F is the largest.

  The portion of the magnetic pole 7A between the bending point 24A, 24B and the tip, the portion of the magnetic pole 7B between the bending point 24C, 24D and the tip, the magnetic pole 7C, the bending point 24E, 24F and the tip Of the magnetic pole 7D, between the bending point 24G, 24H and the tip, between the bending point 24I, 24J of the magnetic pole 7E, and the bending point 24K of the magnetic pole 7F, The portion between 24 L and the tip is disposed at every 60 ° around the incident electrode 18 in the horizontal direction.

  In the present embodiment, as described later, an orbit concentric area centering on the incident electrode 18 (ion injection port of the ion incident tube 3A) and an orbit eccentric area surrounding the orbit concentric area are formed. Orbital concentric regions are formed in a constant region inside the respective bending points of the magnetic poles 7A to 7F. Therefore, the shape inside the bending point of each magnetic pole has a shape similar to that of a six-sector radial sector type AVF cyclotron. In the orbital concentric area, the centers of the respective annular beam orbits formed in the orbital concentric area do not change for each annular beam orbit in which ion beams having different energies circulate. That is, the strength of the magnetic field, that is, the convergence and divergence of the beam can be obtained at a predetermined timing in the cycle of the beam orbit or at a predetermined orbit angle where the magnetic poles are disposed radially to the center of the beam orbit. The magnetic poles are formed to be able to

  The magnetic pole 7A and the magnetic pole 7B, the magnetic pole 7C and the magnetic pole 7D, the magnetic pole 7E and the magnetic pole 7F, the recess 29F and the recess 29B, and the recess 29E and the recess 29C have symmetrical shapes with respect to the dashed dotted line X, respectively. ing. Of the six magnetic poles (convex portions) 7A to 7F formed on each of the iron cores 14A and 14B, the magnetic poles 7A, 7C, and 7E are straight lines connecting the central axis C of the annular coil and the entrance of the beam emission path 20. On the other hand, they are installed in line symmetry with the magnetic poles 7B, 7D and 7F. At the same time, the magnetic pole shape shown in the present embodiment is not installed in rotational symmetry as a whole with respect to the center of the circular iron core, the center of gravity of the annular coil, or the ion incident point. The reason is that even if the center of the beam orbit is gradually displaced for each energy, at a predetermined timing in the period of each beam orbit or as a result, with respect to the center of each beam orbit The reason is to obtain the strength of the magnetic field, that is, the convergence and the divergence of the beam at approximately the same rotation angle. For this reason, the magnetic pole shape is axisymmetric with respect to the direction in which the center of the beam circling orbit deviates, and is installed so as to be inclined diagonally in the opposite direction in which the center deviates. Become. In such a magnetic pole shape, the center of gravity of the six pole portions is displaced in the opposite direction in which the center of the beam orbit is displaced from the center of the iron core. Located at the coordinates of. The relationship between the magnetic pole shape and the beam orbit will be described later in detail using FIG.

  The trim coil 8A is disposed on the magnetic pole 7A, and the lead wires 21A and 21B are connected to both ends of the trim coil 8A. The trim coil 8B is disposed on the magnetic pole 7B, and the lead wires 21C and 21D are connected to both ends of the trim coil 8B. The trim coil 8C is disposed on the magnetic pole 7C, and the lead wires 21E and 21F are connected to both ends of the trim coil 8C. The trim coil 8D is disposed on the magnetic pole 7D, and the lead wires 21G and 21H are connected to both ends of the trim coil 8D. The trim coil 8E is disposed on the magnetic pole 7E, and the lead wires 21I and 21J are connected to both ends of the trim coil 8E. The trim coil 8F is disposed on the magnetic pole 7F, and the lead wires 21L and 21K are connected to both ends of the trim coil 8F. Each of the lead wires 21A to 21K passes through between the annular coil 11A and the annular coil 11B, penetrates the cylindrical portion 75B, and is taken out of the vacuum vessel 27.

  Since each of the trim coils 8A to 8F is installed on each of the magnetic poles 7A to 7F according to the magnetic field that is desired to be generated there in order to generate an isochronous magnetic field at the intermediate surface 77, The intervals are not constant. In each of the magnetic poles 7A to 7F, the closer to the inner surface of the annular coil than to the incident electrode 18, the narrower the distance between the trim coils disposed. Further, in the magnetic poles 7A, 7C and 7E, the distance between the trim coils disposed in the order of the magnetic poles 7A, 7C and 7E becomes narrow. In the magnetic poles 7B, 7D and 7F, the distance between the trim coils disposed in the order of the magnetic poles 7B, 7D and 7F becomes narrow. Because the wide energy beam orbit 78 is focused in a narrow radial area of the annular coil near the entrance of the beam exit path 20, the trim coils installed in the poles 7E and 7F adjacent to the entrance of the beam exit path 20 The distance between the two is narrowed at their outer periphery to correspond to the required magnetic field gradient of that radius and the high energy beam orbit.

  The arrangement of the high frequency accelerating electrodes 9A, 9B, 9C and 9D in the return yoke 5B will be described with reference to FIGS.

  The high frequency accelerating electrode 9A is disposed in the recess 29F between the magnetic pole 7A and the magnetic pole 7C, and is connected to the waveguide 10A. The high frequency acceleration electrode 9A is disposed between the bending points 24B and 24E and the annular coil 11B in the recess 29F. The high frequency accelerating electrode 9B is disposed in the recess 29B between the magnetic pole 7B and the magnetic pole 7D, and is connected to the waveguide 10B. The high frequency accelerating electrode 9B is disposed between the bending points 24D and 24G and the annular coil 11B in the recess 29B. The high frequency accelerating electrodes 9A and 9B may have the end face on the ion implantation port side positioned at an intermediate point between the bending points of the high frequency accelerating electrodes 9A and 9B and the ion implantation port. The waveguides 10A and 10B pass through between the annular coil 11A and the annular coil 11B, penetrate the cylindrical portion 75B, and are taken out of the vacuum vessel 27. In the high frequency accelerating electrodes 9A and 9B, the width in the circumferential direction of the annular coil 11B increases from the incident electrode 18 toward the annular coil 11B.

  The high frequency acceleration electrode 9C is disposed in the recess 29E between the magnetic pole 7C and the magnetic pole 7E and connected to the waveguide 10C. The high frequency acceleration electrode 9C is bent at bending points 24M and 24N (see FIG. 4) formed on the two side surfaces. The portion of the high-frequency accelerating electrode 9C between the bending points 24M and 24N and the end face facing the annular coil 11B is bent toward the concave portion 29A (first concave portion) in the direction in which the ion beam circulates. The width of the high frequency accelerating electrode 9C in the circumferential direction of the annular coil 11B decreases from the bent position of each of the bending points 24M and 24N toward the tip, and from these bending points toward the end face facing the annular coil 11B. Increase. The high frequency acceleration electrode 9D is disposed in the recess 29C between the magnetic pole 7D and the magnetic pole 7F and connected to the waveguide 10D. The high frequency accelerating electrode 9D is bent at bending points 24O and 24P (see FIG. 4) formed on the two side surfaces. A portion of high-frequency accelerating electrode 9D between bending points 24O and 24P and an end face facing to annular coil 11B is bent toward recess 29A (first recess) in a direction opposite to the direction in which the ion beam circulates. There is. The width of the high-frequency accelerating electrode 9D in the circumferential direction of the annular coil 11B decreases from the bent positions of the bending points 24O and 24P toward the tip, and from these bending points toward the end face facing the annular coil 11B. Increase. The waveguides 10C and 10D pass through between the annular coil 11A and the annular coil 11B, pass through the cylindrical portion 75B, and are taken out of the vacuum vessel 27. The respective tips of the high frequency acceleration electrodes 9C and 9D are located on the side of the incidence electrode 18, and are connected to each other in the ion incidence area where the incidence electrode 18 is provided. The incidence electrode 18 faces the connecting portion of the high frequency accelerating electrode 9C and the high frequency accelerating electrode 9D, and is disposed in the beam circulation area 76 in a state of being separated from the connecting portion.

  The recess 29 A, the incidence electrode 18 and the recess 29 D are disposed along a dashed dotted line X passing through the central axis C of the vacuum vessel 27.

  As shown in FIG. 6, each of the magnetic poles 7A to 7F formed on the base portion 74A of the return yoke 5A is a convex portion protruding from the cylindrical portion 75A. Also in the return yoke 5A, similarly to the return yoke 5B, a recess 29G in which the annular coil 11A is disposed is formed between each of the magnetic poles 7A, 7B, 7C, 7D, 7E and 7F and the cylindrical portion 75A. (See Figure 6).

  When the return yoke 5A and the return yoke 5B face each other and are coupled to each other, the magnetic poles 7A, 7B, 7C, 7D, 7E, and 7F face each other. In such a combined state of the return yoke 5A and the return yoke 5B, the recesses 29A, 29B, 29C, 29D, 29E, and 29F also face each other.

  Further, with respect to the intermediate surface 77, the magnetic poles 7A formed on each of the return yokes 5A and 5B, the magnetic poles 7B, the magnetic poles 7C, the magnetic poles 7D, the magnetic poles 7E and the magnetic poles 7F, Furthermore, the recesses 29A formed in each of the return yokes 5A and 5B have a shape in which the recesses 29B are the same, the recesses 29C are the same, the recesses 29D are the same, the recesses 29E are the same, and the recesses 29F are the symmetry. .

  The bottom surface 95 of the recess 29A formed in the return yoke 5A and the bottom surface 95 of the recess 29A formed in the return yoke 5B are closest to each other at the position of the ion incident tube 3A as shown in FIG. In the vacuum vessel 27, these bottom surfaces 95 are inclined toward the massless septum 12 located 180 ° opposite to the entrance of the beam exit path 20 from the entrance electrode 18, specifically, in the recess 29A. The width in the central axis C direction between these bottom surfaces 95 also gradually widens from the ion injection tube 3A toward the massless septum 12. At the position where the massless septum 12 is disposed, the width between the bottom surface 95 of the recess 29A formed in the return yoke 5A and the bottom surface 95 of the recess 29A formed in the return yoke 5B is formed between these bottom surfaces 95. It is the widest within the

  The bottom surface 95 of the recess 29D formed in the return yoke 5A and the bottom surface 95 of the recess 29D formed in the return yoke 5B are also closest to each other at the position of the ion incident tube 3A, as shown in FIG. In the vacuum vessel 27, these bottom surfaces 95 are inclined surfaces from the position of the ion entrance tube 3A toward the septum electromagnet 19, and the width in the central axis C direction between these bottom surfaces 95 is also the ion entrance tube 3A. Gradually wide toward the septum electromagnet 19. The width between the bottom surface 95 of the portion where the annular coil 11A of the recess 29D formed in the return yoke 5A is disposed and the bottom surface 95 of the portion where the annular coil 11A of the recess 29D formed in the return yoke 5B is The width is the same as the width between the bottom surface 95 of the portion where the massless septum 12 of the recess 29A formed in the yoke 5A is disposed and the bottom surface 95 of the portion where the massless septum 12 of the recess 29A formed in the return yoke 5B is disposed. It is.

  In the iron core 14A, the magnetic poles 7A to 7F, the base portion 74A and the cylindrical portion 75A are integrated to form an iron core 14A. In the iron core 14B, the magnetic poles 7A to 7F, the base portion 74B, and the cylindrical portion 75B are integrated to form an iron core 14B.

  As shown in FIG. 6, a gap 28A is formed between the magnetic pole 7A of the return yoke 5A and the magnetic pole 7A of the return yoke 5B opposed thereto, and between the magnetic poles 7B opposed in the axial direction of the vacuum vessel 27. The gap 28B is formed between the magnetic pole 7C of the return yoke 5A and the magnetic pole 7C of the return yoke 5B opposite to the magnetic pole 7C of the return yoke 5A, and the magnetic pole 7D of the return yoke 5A and this A gap 28D is formed between the opposing magnetic poles 7D of the return yoke 5B. Although not shown, between the magnetic pole 7E of the return yoke 5A and the magnetic pole 7E of the return yoke 5B facing this and between the magnetic pole 7F of the return yoke 5A and the magnetic pole 7F of the return yoke 5B facing this Also, gaps are respectively formed. Furthermore, a gap is also formed between the high frequency accelerating electrode 9A of the return yoke 5A and the high frequency accelerating electrode 9A of the return yoke 5B facing it, and the high frequency accelerating electrode 9B of the return yoke 5A and the return facing it A gap is also formed between the high frequency accelerating electrodes 9B of the yoke 5B. Although not shown, the high frequency accelerating electrode 9C of the return yoke 5A is opposed to the high frequency accelerating electrode 9C of the return yoke 5B and the high frequency accelerating electrode 9D of the return yoke 5A is opposed to the return yoke 5B. Similarly, gaps are formed between the high frequency accelerating electrodes 9D.

  The gaps formed between the magnetic poles described above and the gaps formed between the high frequency accelerating electrodes all include the intermediate surface 77, and a beam circulation region 76 in which the ion beam circulates in the horizontal direction. Form

  A massless septum 12 is disposed in a recess 29A formed in each of the return yokes 5A and 5B (see FIG. 5), and is located between the magnetic pole 7A and the magnetic pole 7B. The massless septum 12 will be described in detail with reference to FIGS. 7 and 8. The massless septum 12 and an energy absorber 62 described later are beam deviating devices for shifting the ion beam from the beam orbit around which it is orbiting.

  The massless septum 12 includes an iron core member 30 and coils 33A and 33B. Iron core member 30 includes iron core portions 31A and 31B and iron connection portion 31C. The flat-plate shaped iron core portion 31A and the flat-plate shaped iron core portion 31B face each other and are arranged in parallel, and one end portions of the iron core portions 31A and 31B are connected by the connecting portion 31C. A plurality of (for example, 28) magnetic poles 32A, which are projecting parts, are formed on the surface of the core 31A facing the core 31B, and these magnetic poles 32A have a predetermined interval in the longitudinal direction of the core 31A. Are arranged in a row. Coils 33A are separately wound around each pole 32A. A plurality of (for example, 28) magnetic poles 32B which are protrusions are formed on the surface of the core 31B facing the core 31A, and these magnetic poles 32B have a predetermined interval in the longitudinal direction of the core 31B. Are arranged in a row. Coils 33B are separately wound around each magnetic pole 32B.

  A wire 23A is connected to each end of each coil 33A. A plurality of wires 23A are bundled, and as shown in FIG. 8, one bundle of wires 23A is attached to one side of iron core 31A, and another bundle of wires 23A is attached to the other side of iron core 31A. . Also, one wire 23B is connected to each end of each coil 33B. A plurality of wires 23B are also bundled, and as shown in FIG. 8, one bundle of wires 23B is attached to one side of iron core 31B and the other bundle of wires 23B is attached to the other side of iron core 31B. .

  The plurality of magnetic poles 32A formed in the core portion 31A and the plurality of magnetic poles 32B formed in the core portion 31B are disposed such that the magnetic poles 32A and the magnetic poles 32B face each other. A beam passage 35 is formed between each of the magnetic poles 32A and each of the magnetic poles 32B, which is a gap through which the circulating ion beam passes. The beam passage 35 includes a part of the intermediate surface 77.

  One end portion of the rod-like operation member 16 is attached to the connecting portion 31C in which the through hole 31D of the massless septum 12 is formed. The operation member 16 is also a support member of the massless septum 12 and is connected to the piston of the moving device 17 having a piston and a cylinder (see FIG. 3). A position detector 38 for detecting the position of the massless septum 12 in the vacuum vessel 27 is attached to the moving device 17 (see FIG. 1). The operation member 16 is disposed between the annular coil 11A and the annular coil 11B, and is slidably attached to the cylindrical portion 75B through, for example, the cylindrical portion 75B of the return yoke 5B. The moving device 17 may be a motor. When a motor is used as the moving device 17, an encoder is used as the position detector 38, and this encoder is connected to the rotation shaft of the motor.

  The massless septum 12 is a deflection electromagnet device that deflects the ion beam at different positions in the radial direction of the annular coil disposed in the return yoke.

  The beam current measuring device 98 includes a beam current measuring unit 15, a moving device 17A and a position detector 39. The beam current measurement unit 15 is disposed on the center axis C of the vacuum vessel 27 and the dashed dotted line X passing through the incident electrode 18 at the position of the recess 29A at the intermediate surface 77 in the vacuum vessel 27 (see FIG. 3). A rod-like operation member 16A connected to the beam current measurement unit 15 penetrates the vacuum vessel 27 and extends to the outside of the vacuum vessel 27. The operation member 16A is also a support member for the beam current measurement unit 15, and is connected to the piston of the moving device 17A having a piston and a cylinder outside the vacuum vessel 27. The operation member 16A is disposed between the annular coil 11A and the annular coil 11B, and is slidably attached to the cylindrical portion 75B through, for example, the cylindrical portion 75B of the return yoke 5B. A position detector 39 for detecting the position of the beam current measurement unit 15 in the vacuum vessel 27 is attached to the moving device 17A (see FIG. 1). The moving device 17A may be a motor. When a motor is used as the moving device 17A, an encoder is used as the position detector 39, and this encoder is connected to the rotation shaft of the motor.

  The operation member 16A is inserted into the beam passage 35 formed between the plurality of magnetic poles 32A and the plurality of magnetic poles 32B of the massless septum 12 through the through holes 31D formed in the coupling portion 31C (see FIG. 5). Therefore, when the operation member 16A moves in the radial direction of the vacuum vessel 27 along the alternate long and short dash line X, the beam current measurement unit 15 moves in the beam passage 35 in the intermediate surface 77. At this time, at the position of the recess 29A on the alternate long and short dash line X along the end face of each magnetic pole 32A of the massless septum 12, the distance between the beam orbits 78 is wide. The beam current can be easily measured on each of the beam orbits 78 by moving and measuring on the alternate long and short dash line X in the radial direction of

  The waveguide 10D connected to the high frequency accelerating electrode 9D is connected to the high frequency power source 36 (see FIG. 1). The waveguides 10A, 10B and 10C connected to the other high frequency accelerating electrodes 9A, 9B and 9C are also connected to the high frequency power sources 36 provided for each of the high frequency accelerating electrodes, though not shown. The lead wires 21C and 21D respectively connected to both ends of the trim coil 8B provided on the magnetic pole 7B are connected to the power supply 37 (see FIG. 1). Although not shown, the above-described lead wires connected to the respective ends of trim coils 8A and 8C to 8F provided on the other magnetic poles 7A and 7C to 7F, respectively, are also provided for each power supply provided for each magnetic pole. Connected to 37 Although the high frequency power supply and the magnetic pole described above exist in the return yoke 5B, the high frequency accelerating electrodes 9A to 9D are also connected to different high frequency power supplies 36 in the return yoke 5A, and each of the magnetic poles 7A to 7F is a separate power supply. Connected to 37 Furthermore, the incident power supply 18 is connected to the power supply 82 by the wiring 81 (see FIG. 1).

  The two lead wires 22 connected to the annular coil 11B provided in the return yoke 5B are connected to the power supply 57 (see FIG. 1). The two lead wires 22 connected to the annular coil 11A provided in the return yoke 5A are connected to the power supply 57 described above. The aforementioned wires 23A and 23B connected to each of the coils 33A and 33B wound around each of the magnetic poles 32A and 32B of the massless septum 12 are connected to one power supply 40 (see FIG. 1). .

  An excitation current is supplied from the power source 57 to the annular coils 11A and 11B through the respective lead wires 22. The iron cores 14A and 14B are magnetized by the action of the excitation current. The excitation current from each power source 37 is provided to the magnetic poles 7A to 7F through the lead wire 21A, the lead wire 21C, the lead wire 21E, the lead wire 21G, the lead wire 21G, the lead wire 21I, and the lead wire 21K. To 8F to excite each of the magnetic poles 7A to 7F. Activate the ion source 3 A high frequency voltage from each high frequency power source 36 is applied to each of the high frequency accelerating electrodes 9A to 9D through each of the waveguides 10A to 10D. The voltage from the power supply 82 is applied to the incidence electrode 18.

  As the iron cores 14A and 14B are magnetized, the magnetic poles 7A to 7F formed on the return yoke 5B, respectively, the magnetic poles 7A to 7F formed on the return yoke 5A facing the respective magnetic poles, the return yoke 5A The closed magnetic circuit of each of the magnetic pole 7A to 7F formed on the base portion 74A, the cylindrical portion 75A of the return yoke 5A, the cylindrical portion 75B of the return yoke 5B, the base portion 74B of the return yoke 5B and the return yoke 5B. Occur. At this time, magnetic lines of force are also generated from the bottom surfaces 95 of the recesses 29A to 29F formed in the return yoke 5B toward the bottom surfaces 95 of the recesses 29A to 29F formed in the return yoke 5A. . The lines of magnetic force generated between the opposed bottom surfaces 95 are smaller than the lines of magnetic force generated between the opposed magnetic poles. The magnetic field formed between the opposing magnetic poles (convex portions) is higher than the magnetic field formed between the opposing recesses.

  As a result, the magnetic field distribution shown in FIG. 10 is formed at the intermediate surface 77 in the vacuum vessel 27. This magnetic field distribution shows the distribution of isochronous magnetic fields. The isochronous magnetic field is a magnetic field in which the time for which the ion beam goes around does not change even if the energy of the ion beam to be accelerated increases and the radius of the beam orbit which the ion beam goes up increases. This isochronous magnetic field is formed by the magnetic poles 7A to 7F. “High” shown in FIG. 10 indicates a region where the magnetic field strength is high, and “low” indicates a region where the magnetic field strength is low. Regions with high magnetic field strength and regions with low magnetic field strength are alternately formed around the ion injection port, ie, the incident electrode 18. The highest magnetic field strength in the high magnetic field strength region is, for example, 2.2 T, and the lowest magnetic field strength in the low magnetic field strength region is, for example, 0.84 T. In the present embodiment, there are six regions in which the magnetic field strength is high and the regions in which the magnetic field strength is low. The position of the incident electrode 18 and the position of the septum electromagnet 19 (in FIG. 10, the point (aggregated point) at which the beam orbit 78 is shifted to the septum electromagnet 19 and the plural beam orbits 78 are integrated) coincide When FIG. 3 and FIG. 10 are superimposed, the six regions with high magnetic field strength overlap one of the magnetic poles 7A to 7F shown in FIG. That is, each magnetic pole is disposed in each region where the magnetic field strength is high. Also, the six regions with low magnetic field strength overlap with one of the recesses 29A to 29F shown in FIG. That is, each recess is arranged in each region where the magnetic field strength is low.

Ions (for example, protons (H ⁺ )) emitted from the ion source 3A are incident on the beam circulation area 76 through the ion injection tube 3A, and travel in the beam circulation area 76 by the action of the incident electrode 18 to which a voltage is applied. The direction can be bent horizontally. The incident protons are accelerated by the high frequency accelerating electrodes 9A to 9D in a state where the magnetic poles 7A to 7F and the annular coils 11A and 11B are excited. The protons are accelerated by the high frequency accelerating electrodes 9C and 9D in a region near the incidence electrode 18, and accelerated by the high frequency accelerating electrodes 9A to 9D in a region near the annular coils 11A and 11B. The accelerated protons make a proton ion beam (hereinafter simply referred to as an ion beam) and orbit at the intermediate surface 77 along a beam orbit formed around the incident electrode 18. Specifically, in order to cause betatron oscillation in the direction perpendicular to the intermediate surface 77, the ion beam orbits within the beam circulation region 76 having a predetermined width in the perpendicular direction centering on the intermediate surface 77.

  FIG. 10 shows the beam orbits 78 at the intermediate plane 77 inside the annular coil 11B, and the distribution of the magnetic field strength, and also shows a plurality of isochronous lines 79. An isochronous line is a line connecting the positions of circulating ions (eg, protons) present at the same time. The respective isochronous lines 79 shown by dotted lines in FIG. 10 extend radially from the incident electrode 18 and are bent halfway (at the position of the beam orbit of the 35 MeV ion beam). The side surfaces of the magnetic poles 7A to 7F provided on the return yokes 5A and 5B correspond to the corresponding isochronous lines 79 shown in FIG.

  The beam orbits 78 formed in the beam orbiting area 76 in the accelerator 4 are a plurality of orbits as shown in FIG. In FIG. 10, when the energy of the ion beam is in the range of 250 MeV or less, every 0.25 MeV in the energy region of 0.5 MeV or less and every 0.5 MeV in the energy region of more than 0.5 MeV and 1 MeV or less. More than 1 MeV to less than 10 MeV, every 1 MeV, more than 10 MeV to less than 50 MeV, every 5 MeV, more than 50 MeV to less than 100 MeV, every 10 MeV, more than 100 MeV Beam orbits 78 are shown every 20 MeV in the energy range of 220 MeV or less, and every 15 MeV in the energy range of more than 220 MeV to 250 MeV.

  Each of the beam orbits 78 around which each ion beam having an energy of 35 MeV or less is an annular beam orbit centered on the incident electrode 18. Each of the beam orbits 78 around which each ion beam having an energy of more than 35 MeV orbits is an annular beam orbit eccentric from the incident electrode 18. As a result, between the incidence electrode 18 and the septum electromagnet 19, the centers of the beam orbits 78 of the respective ion beams having an energy exceeding 35 MeV are deviated away from the entrance of the beam emission path 20. At the entrance side of the emission path 20, the distances between the beam orbits 78 are close. In particular, the respective beam orbits 78 of each ion beam having an energy of more than 60 MeV are concentrated within a certain range at the entrance side of the beam exit path 20. Further, on the opposite side of the entrance electrode 18 from the entrance of the beam exit path 20 180 °, the beam orbits 78 of each ion beam having energy exceeding 35 MeV are the entrance electrode 18 and the beam exit path 20. The distance between the beam orbits 78 is increased by the distance between the beam orbits 78 being smaller.

  The protons which are bent in the horizontal direction in the beam circulation area 76 by the incidence electrode 18 after passing through the ion injection tube 3A become an ion beam having a low energy and a beam circulation orbit in which an ion beam having a low energy circulates. I will go along. This ion beam is a portion between bending points 24M and 24N of high frequency accelerating electrode 9C to which high frequency voltage is applied and the tip, and bending points 24O and 24P of high frequency accelerating electrode 9D to which high frequency voltage is applied and the tip And accelerate to a portion between them, and transfer to the beam orbit 78 located outside. For example, the 10 MeV ion beam orbiting the 10 MeV ion beam orbit 78 is accelerated by the above portion of the high-frequency accelerating electrodes 9C and 9D and located outside, the 11 MeV ion beam orbit It shifts to 78 and orbits along the beam orbit 8. In this way, it is assumed that the circulating ion beam is accelerated and sequentially transferred to the outer beam orbit 78, and is transferred to the beam orbit 78 of the 119 MeV ion beam, for example. The 119 MeV ion beam orbiting this beam orbit 78 is accelerated by the high-frequency accelerating electrodes 9A to 9D, and is transferred toward the beam orbit 78 of the outer 220 MeV ion beam.

  The 220 MeV ion beam orbiting along the beam orbit 78 of the 220 MeV ion beam is kicked out of the beam orbit 78 by the massless septum 12, ie, it is released from the beam orbit 78 Thus, the beam is emitted to the beam path 48 of the beam transport system 13 through the beam emission path 20 formed in the septum electromagnet 19. Further, the 140 MeV ion beam orbiting along the beam orbit 78 of the 140 MeV ion beam is emitted to the beam path 48 through the beam exit path 20 by being kicked out by the massless septum 12. As described above, it is possible to emit ion beams having different energies from the accelerator 4 of the ion beam generator 2. The beam orbits 78 are shifted to the entrance side of the beam exit path 20 between the entrance electrode 18 and the entrance of the beam exit path 20, and the distance between the beam orbits 78 is close. This is realized by the fact that the distance between the beam orbits 78 is wide on the opposite side of the entrance of the beam exit path 20 from the entrance electrode 18 and at the entrance of the beam exit path 20. In particular, a plurality of beam orbits 78 around which ion beams having different energies circulate are concentrated on the inlet side of the beam emission path 20 in the later-described orbital eccentric region, which contributes to the emission of ion beams having different energies. The details of the function of the massless septum 12 will be described later.

  The accelerator 4 used in the present embodiment has a plurality of concentric circles centered on the incidence electrode 18 (ion implantation port of the ion incidence tube 3A) on the intermediate surface 77 where the beam orbits 78 in the beam circulation area 76 are formed. An orbital concentric area (for example, a beam orbit 78 shown in FIG. 10 in which a 35 MeV ion beam circulates and in which the beam orbit 78 is shown), and A plurality of annular beam orbits decentered with each other are formed around the concentric area, and the annular beam orbits are closely spaced between the entrance electrode 18 and the entrance of the beam exit path 20, and vice versa. On the other side of the entrance of the beam exit path 180 180 ° opposite to the entrance electrode 18, the annular beam orbits are widely spaced from each other (eg, Indicated at 10, outside the region) is formed than the beam orbit 78 ion beam 35MeV circulates.

  Each of the bending points 24M to 24P formed on the high frequency accelerating electrodes 9C and 9D disposed in the vacuum vessel 27 is also, for example, the position of the beam orbit 78 where the 35 MeV ion beam orbits as shown in FIG. It is located in

In accelerator 4, along the isochronous lines IL _1, 11, along the isochronous line IL ₂ changes in the gap between the magnetic poles 7E return yoke 5B facing the magnetic pole 7E return yoke 5A and this and, the change in the gap between the pole 7C of the return yoke 5B facing the magnetic pole 7C of the return yoke 5A therewith along 12, and isochronous line IL _3, and pole 7A of the return yoke 5A and this Changes in the gap between the opposing return yoke 5B and the magnetic pole 7A are shown in FIG. The gaps shown in FIG. 11, FIG. 12 and FIG. 13 show one half of each of the gap between the opposing magnetic poles 7E, the gap between the opposing magnetic poles 7C, and the gap between the opposing magnetic poles 7A. These gaps correspond to the gap between the magnetic pole 7E and the intermediate surface 77, the gap between the magnetic pole 7C and the intermediate surface 77, and the gap between the magnetic pole 7A and the intermediate surface 77. The above-described isochronous lines IL ₁ , IL ₂ and IL ₃ are shown in FIGS. 3 and 10, respectively. In the horizontal direction, each of the isochronous lines IL ₁ , IL ₂ and IL ₃ corresponds to the center line of each of the magnetic poles 7E, 7C and 7A.

As shown in FIG. 11, the gap between the magnetic pole 7E and the intermediate surface 77 is the tip of the magnetic pole 7E facing the incident electrode 18 and the end face of the magnetic pole 7E facing the inner surface of the annular coil 11B. The length along the isochronous line IL ₁ is most narrow at a position preferably in the range of 93.0% to 96.0% from the tip thereof. This indicates that the height in the direction of the central axis C on the center line of the magnetic pole 7E (the height of the magnetic pole 7E from the bottom surface 95 of each of the concave portions 29D and 29E) is the highest at the position within this range. . The height of the magnetic pole 7F arranged symmetrically to the magnetic pole 7E with respect to the alternate long and short dash line X in the direction of the central axis C on the center line of the magnetic pole 7F As in the case of the magnetic pole 7E, the length of the magnetic pole 7F along the center line is the highest at a position within the range from the tip facing the incident electrode 18.

As shown in FIG. 12, the gap between the magnetic pole 7C and the intermediate surface 77 is the distance between the tip of the magnetic pole 7C opposite to the incident electrode 18 and the end face of the magnetic pole C opposite to the inner surface of the annular coil 11B. The length along the isochronal line IL ₂ is the narrowest at a position preferably within the range of 86.2% to 89.2% from its tip. This indicates that the height in the direction of the central axis C on the center line of the magnetic pole 7C (the height of the magnetic pole 7C from the bottom surface 95 of each of the concave portions 29E and 29F) is the highest at the position within this range. . The height in the direction of the central axis C on the center line of the magnetic pole 7D of the magnetic pole 7D arranged symmetrically with the magnetic pole 7C with respect to the alternate long and short dash line X As in the case of the magnetic pole 7C, the length of the magnetic pole 7D along the center line is the highest at a position within the range from the tip facing the incident electrode 18.

Further, as shown in FIG. 13, the gap between the magnetic pole 7A and the intermediate surface 77 is the tip of the magnetic pole 7A facing the incident electrode 18 and the end face of the magnetic pole A facing the inner surface of the annular coil 11B. The distance between the tip and the isochronous line IL ₃ is the narrowest at a position preferably within the range of 88.7% to 91.7%. This indicates that the height in the direction of the central axis C on the center line of the magnetic pole 7A (the height of the magnetic pole 7A from the bottom surface 95 of each of the recessed portions 29A and 29F) is the highest at a position within this range. . The height of the magnetic pole 7B arranged symmetrically with the magnetic pole 7A with respect to the alternate long and short dash line X in the central axis C direction on the center line of the magnetic pole 7B As in the case of the magnetic pole 7A, the length of the magnetic pole 7B along the center line is the highest at a position within the range from the tip facing the incident electrode 18. Although not shown, the position in the central axis C direction of the bottom surface 95 of the recess 29E is the same as each position in the central axis C direction of the bottom surface 95 of each of the recesses 29A to 29C, 29F.

  In the return yoke 5A, the heights of the magnetic poles 7E and 7F in the central axis C direction on the center lines of the respective magnetic poles are also the highest at the positions of the magnetic poles 7E and 7F of the return yoke 5B. In the return yoke 5A, the heights of the magnetic poles 7C and 7D in the direction of the central axis C on the center lines of the respective magnetic poles are also the highest at the positions of the magnetic poles 7C and 7D of the return yoke 5B. The heights of the magnetic poles 7A and 7B in the direction of the central axis C on the center lines of the respective magnetic poles are also the highest at the positions of the magnetic poles 7A and 7B of the return yoke 5B within the above range.

  As a result, in the magnetic field strength distribution on the intermediate surface 77 between the return yoke 5B and the return yoke 5A, the magnetic poles 7E and 7F of the return yoke 5B face the magnetic poles 7E and 7F at positions within the above range. Magnetic field strengths between the magnetic poles 7E and 7F of the return yoke 5A, the magnetic poles 7C and 7D of the return yoke 5A facing the magnetic poles 7C and 7D at positions in the above range in the magnetic poles 7C and 7D of the return yoke 5B. And the magnetic field strength between each of the magnetic poles 7A and 7B of the return yoke 5A opposite to the magnetic poles 7A and 7B at a position within the above range in the magnetic poles 7A and 7B of the return yoke 5B. Is the highest as in 2.2 T shown in FIG. Thereby, the magnetic field strength at the intermediate surface 77 is 200 MeV in the region inside the respective inner surfaces of the annular coils 11A and 11B in the region where the magnetic poles 7A to 7F are arranged, for example, as shown in FIG. And the highest at the position of the beam orbit 78 at 180 MeV. Such a distribution of magnetic field strength makes it possible to apply a focusing force in a direction perpendicular to the beam orbit, and allows the ion beam to orbit stably along the beam orbit 78.

  In the accelerator 4 used in the present embodiment, since the magnetic field distribution at the intermediate surface 77 is not uniform, the beam circulation orbit 78 formed is annular but not a perfect circle. As described above, in the iron cores 14A and 14B, the magnetic field strength of the portions where the magnetic poles (convex portions) 7A to 7F are located is stronger than that of the portions where the respective recesses 29A to 29F are located. Between the opposing magnetic poles formed in each of the above, the curvature of the beam orbit becomes large. The above-mentioned pair of opposing magnetic poles are arranged at six positions per one circumference of the beam orbit 78. For this reason, each beam orbit has a generally hexagonal shape. In FIG. 14, as the amplitude of the magnetic field strength along the beam orbit is larger, the tendency becomes stronger. If the amplitudes of the magnetic field strengths are the same, the lower the energy side of the beam orbit, the more likely the ion beam is to bend, so the tendency becomes stronger. The center of a non-round beam orbit is the center of gravity of the orbit shape and is the point that is the arithmetic mean of the orbit coordinates.

  In the case of a general cyclotron, as the energy of the ion beam increases, the ion beam becomes less likely to bend and the focusing becomes more difficult as the beam orbits on the outer periphery. For this reason, it is necessary to increase the amplitude of the magnetic field intensity along the beam orbit shown in FIG. That is, the magnetic field strength in the radial direction along the center line of each magnetic pole is generally designed so as to be maximum at the beam orbit of the maximum energy (the beam orbit at the outermost periphery).

  The characteristics of the accelerator 4 according to the present embodiment will be described with reference to FIGS. Hereinafter, unless otherwise specified, the direction perpendicular to the central axis C is referred to as “horizontal direction”, and the direction of the central axis C, that is, the direction perpendicular to the intermediate surface 77 is referred to as “vertical direction”.

  FIG. 14 shows the magnetic field strengths along each of the beam orbits 78 in four beam orbits 78 in which each of the ion beam of 0.5 MeV, ion beam of 70 MeV, ion beam of 160 MeV and ion beam of 235 MeV travels separately. Shows the distribution of The traveling direction distance is “0” at each entrance of the beam emission path 20 formed at the septum electromagnet 19 (the outlet of the accelerator 4) in the vicinity of the entrance (the outlet of the accelerator 4). The positions of the intersections with the beam orbit 78 are shown. The position at which the traveling direction distance is “1” is a position obtained by rotating the beam orbit 78 half from the exit of the accelerator 4. In each of the beam orbits 78, the magnetic field intensity changes as shown in FIG. 14 along the beam orbits 78, so that a converging force (amplitude) can be secured. The orbit 78 can be stably orbited. In the beam circulation orbit 78 in which the ion beam of 235 MeV circulates, the converging power is secured by the distribution of the magnetic field intensity which is not a simple sine wave, and the ion beam can be stably orbited in the corresponding beam circulation orbit. Specifically, among the six maximum peaks of the magnetic field intensity passing during one round, the maximum peaks at the second and fifth from the position at which the traveling direction distance is 0 are The magnetic field is formed such that the values of the minimum peaks on either side of their maximum peaks are lower than the others and higher than the others. For this reason, the beam orbit of the 235 MeV ion beam has a smaller amplitude of fluctuation of the passing magnetic field strength than the beam orbit of the 160 MeV ion beam inside.

  FIG. 15 shows the change of the gradient of the normalized magnetic field along the beam orbit 78. The normalized magnetic field is an n value represented by equation (1).

Where B is the magnetic field strength, Bρ is the magnetic rigidity of the ion beam, and B _z is the perpendicular component of the magnetic field. r is a position coordinate in a direction perpendicular to the beam orbit in the orbital plane which is the intermediate plane 77, and the outward direction is positive. When n <1, the ion beam orbiting the beam orbit converges in the horizontal direction, and when n> 0, the ion beam orbiting the beam orbit converges in the vertical direction.

  In three beam orbits 78 in which the 70 MeV ion beam, the 160 MeV ion beam, and the 235 MeV ion beam respectively rotate separately, the traveling direction distance is n at a position of “1” (a half circumference position from each intersection below) Although the value is a small value, the position of each intersection point of a straight line (dotted dotted line X) connecting the entrance and the central axis C and each beam orbit 78 in the vicinity of the entrance of the beam exit path 20 (exit of accelerator 4) That is, the absolute value of the n value becomes large near the position where the traveling direction distance of each beam orbit 78 is “0”). This is because, as described above, when the traveling direction distance is “0”, the beam orbits of each energy are concentrated, and the distance between adjacent beam orbits is small. As a consequence of this, the magnetic field gradient, that is, the absolute value of the n value becomes large, and conversely, when the traveling direction distance between adjacent beam orbits is large, the magnetic field gradient is The absolute value decreases. As described above, by causing the focusing action in the horizontal direction and the focusing action in the vertical direction to alternately act on the ion beam that is alternately orbiting along the beam orbit, the ion beam can stably orbit in both the horizontal direction and the vertical direction. can do.

  The characteristics shown in FIG. 15 illustrate the concepts described below. In each annular beam orbit 78, a position (a traveling direction distance is “1” position) opposite to the entrance of the beam outgoing path 20 with respect to the central axis C of the beam orbit 78 (A total of 1⁄4 turns in the counterclockwise direction with a quarter of the turn in the clockwise direction starting from the position where the advancing direction distance is “1” and the 1 in the advancing direction distance) The integral value of the absolute value of n value represented by the above equation (2) is the above-mentioned intersection point of the entrance side of the beam outgoing path 20 of the beam orbit 78 (the traveling direction distance is the position of “0”) (A traveling direction distance is 1⁄4 of the circumference in a clockwise direction and a traveling direction distance is a 1⁄4 circumference in a counterclockwise direction with a traveling direction distance of “0” as a base point. (Sum) is smaller than the integral value of the absolute value of n values.

  The integral value of the absolute value of n values expressed by the above equation (1) corresponds to a half of the circumference of the annular beam orbit around the position 180 ° opposite to the entrance of the beam exit path. Because it is smaller than the integral value of the absolute value of n values for a half turn around the entrance of the beam exit path, each ion beam with different energy can be efficiently exited, and the beam orbit is decentered, When beam orbits of different energies are focused on the entrance side of the beam exit path, the focusing can reduce the inclination of the magnetic field gradient generated on the entrance side of the beam exit path.

Next, the magnetic field distribution will be described in detail. The magnetic field strength B (L ₁ ) at a certain position on a certain beam orbit 78 is expressed by equation (2).

B (L ₁ ) = B ₀ + B ₁ cos (2πL ₁ / L ₂ ) + B ₂ cos (4πL ₁ / L ₂ )
+ B ₃ cos (6πL ₁ / L ₂ ) (2)
Here, B is the magnetic field strength, L ₁ is the distance in the ion beam traveling direction of the beam orbit, L ₂ is the half length of the beam orbit, B ₀ is the central value of the magnetic field strength (average magnetic field received by ion beam Intensity) and B ₁ , B ₂ and B ₃ are Fourier expansion coefficients of the magnetic field strength in the beam orbit 78 for each energy. Incidentally, as a reference wavelength of the length of half of the beam orbit, B ₁ is the amplitude of the 1 harmonic, B ₂ is an amplitude and B ₃ of the second harmonic represents the amplitude of the third harmonic.

In this embodiment, as shown in FIG. 16, when the kinetic energy of the ion beam is equal to or greater than about 180MeV, but the third harmonic of the magnetic field component B ₃ is increased, at the same time, the magnetic field component B ₂ of the second harmonic wave Decrease. Therefore, in each of the beam orbits 78 in which each ion beam having energy of 180 MeV or more circulates, the focusing power of the ion beam can be secured without increasing the maximum magnetic field. Third harmonic field component B ₃ of decreases from a trajectory concentric regions 0MeV to -0.5T within the 35 meV.

  FIG. 16 shows that the absolute value of the rate of change of the magnetic field component of the third harmonic in the magnetic field strength distribution along the annular beam orbit 78 with energy of the ion beam orbiting this beam orbit is from the orbit concentric region It shows that it falls when transitioning to the eccentric region. Furthermore, FIG. 16 shows that the value of the magnetic field component of the third harmonic decreases as the energy of the ion beam increases in the orbit concentric region.

  The absolute value of the rate of change of the magnetic field component of the third harmonic in the magnetic field strength distribution along the beam orbit with energy of the ion beam orbiting the beam orbit, the orbit eccentricity surrounding the orbit concentric area Since the energy decreases when passing to the region, it is possible to efficiently emit ion beams of different energies, and further, the ion beam can be stably accelerated.

  FIG. 17 shows the change in the betatron frequency in the horizontal and vertical directions corresponding to the kinetic energy of the ion beam. The betatron frequency in the horizontal direction increases almost monotonically with the increase of kinetic energy of the ion beam. However, the variation width of the betatron frequency is 0.6 or less in the kinetic energy range of 0 to 250 MeV. The kinetic energy is polarized in the vertical direction around 50 MeV, but the betatron frequency in the vertical direction is less than 0.5 even by the increase of the kinetic energy. For this reason, the ion beam can stably circulate in the beam circulation area 76 formed between the opposing magnetic poles shown in FIG. 6 and between the opposing high frequency electrodes. Furthermore, this ion beam can also pass stably through the beam passage 35 formed in the massless septum 12 shown in FIG.

  FIG. 18 shows a straight line (dot and dash line X) connecting the entrance and the central axis C and each ion beam having an energy of 0.5 MeV, 70 MeV, 160 MeV and 235 MeV in the vicinity of the entrance of the beam outgoing path Indicates the change in the horizontal β function along each beam orbit 78 at each intersection with the beam orbit 78 (distance in the ion beam traveling direction: 0) to a half cycle (distance in the ion beam traveling direction: 1) ing. The β function is an amount that indicates the spatial spread of the ion beam. The massless septum 12 is disposed at a position where the distance in the traveling direction of the ion beam is 1.

  According to FIG. 18, at the position where the massless septum 12 is disposed, the β function in the horizontal direction becomes 10 m or less, and each ion beam having an energy of 0.5 MeV, 70 MeV, 160 MeV, and 235 MeV circulates. Beam orbits 78 can be separated. Therefore, the massless septum 12 can separately kick out the ion beams having these energies, and the accelerator 4 can emit it to the beam transport system 13.

  FIG. 19 shows a half turn (ion beam distance) from the exit (distance in the traveling direction of the ion beam: 0) of each beam orbit 78 where each ion beam having each energy of 0.5 MeV, 70 MeV, 160 MeV and 235 MeV circulates The change of the β function in the vertical direction along each beam orbit 78 at a distance of 1) in the traveling direction is shown. At a distance of 1 in the traveling direction of the ion beam where the massless septum 12 is disposed, the vertical β function of each ion beam having each energy of 70 MeV, 160 MeV and 235 MeV emitted from the accelerator 4 is 3 m The ion beam of these energies can easily pass through the beam path 35 of the massless septum 12 because In addition, since the β function in the vertical direction is 100 m or less which is the limit not to collide with the magnetic poles in the accelerator 4 between the exit of the beam orbits 78 and the half circumference, the high frequency between the opposing magnetic poles In the beam circulation area 76 formed between the acceleration electrodes, stable circulation can be performed without colliding with the magnetic pole and the high frequency acceleration electrode.

  FIG. 20 corresponds to the amount of kicking out of the ion beam orbiting the beam orbit 78 by the excitation of the magnetic pole of the massless septum 12 when emitting the ion beam from the accelerator 4 to the kinetic energy of the ion beam Show. The entrance of the beam emission path 20 formed in the septum electromagnet 19 is located at −720 mm in FIG. 10 with reference to the center of the lowest energy beam orbit. Here, the energy of the ion beam emitted from the accelerator 4 is 70 MeV or more. The “orbital position” shown in FIG. 20 is the beam exit path 20 of the beam orbit 78 which passes the ion beam of each energy not kicked by the massless septum 12 and closest to the entrance of the beam exit path 20. It shows the position near the entrance. The deviation between the orbit position and the entrance of the beam exit path 20 shown in FIG. 20 represents the orbit displacement caused by the kicking of the ion beam from the orbiting beam orbit 78 using the massless septum 12. . The amount of kicking of this ion beam becomes larger as the energy of the circulating ion beam is lower. The excitation current supplied to the coils 33A and 33B provided to the corresponding pair of magnetic poles 32A and 32B of the massless septum 12 is adjusted in accordance with the amount of kicking.

  A pair of opposing magnetic poles 32A and 32B of the massless septum 12 are magnetic field lines (from the magnetic pole 32B to the magnetic pole 32A) in the same direction as the magnetic field lines generated in the recess 29A of the return yoke 5A, 5B where the massless septum 12 is disposed. It generates exciting magnetic field lines) and is excited to strengthen the magnetic field. In the beam passage 35 formed in the massless septum 12, a peak of a magnetic field as shown in FIG. 22 is formed at a predetermined position in the intermediate surface 77 in the radial direction of the vacuum vessel 27. The position of the magnetic field peak corresponds to the position of any of the 28 pairs of selectively magnetizable magnetic poles 32A and 32B formed on the massless septum 12. The ion beam formed by excitation of the opposing pair of magnetic poles 32A and 32B of the massless septum 12 and passing through the locally strong magnetic field region in the beam passage 35 has a curvature compared to the curvature of the beam orbit 78 Becomes larger. Therefore, the betatron oscillation in the horizontal direction is amplified by the amount of excitation of the massless septum 12 and the width of the ion beam, and the ion beam is kicked inward from the circulating beam orbit 78, and the beam It leaves the orbit 78. The position at which the magnetic field strength peaks in the beam passage 35 can be adjusted by changing the position in the radial direction of the pair of magnetic poles 32A and 32B excited by moving the massless septum 12 in the radial direction by the moving device 17. As in the case where the magnetic poles 32A and 32B described above are provided in the massless septum 12, it is possible to accurately adjust the peak generation position of the magnetic field strength.

  FIG. 21 shows that when each of the 70 MeV ion beam, the 160 MeV ion beam and the 235 MeV ion beam is kicked out by the massless septum 12, the kicked out ion beam is formed from the massless septum 12 to the septum electromagnet 19. It shows the displacement from the beam orbit of the corresponding energy in the horizontal direction of the beam orbiting area 76 until the entrance of the beam exit path 20 is reached. FIG. 21 is different from the other drawings in that the massless septum 12 is disposed at a distance of “0” in the traveling direction of the ion beam, and the distance of “1” in the traveling direction of the ion beam (massless septum) The inlet (ion beam extraction position) of the beam emission path 20 is located at a position from 12 to a half circumference). When the displacement in the horizontal direction is a positive value, it means that the kicked ion beam is displaced toward the outside of the beam orbit 78, and the displacement in the horizontal direction (displacement in the intermediate surface 77) Is a negative value, this means that the kicked ion beam is displaced toward the inside of the beam orbit 78. The ion beam kicked to the inside of the beam orbit by the massless septum 12 is displaced to the inside of the beam orbit to a large extent toward the outside of the beam orbit according to the betatron oscillation in the horizontal direction after being displaced to a certain extent. The massless septum 12 is controlled such that the smaller the energy of the circulating ion beam, the larger the absolute value of the horizontal displacement of the kicked-out ion beam, and the displacement of the beam orbit outside the ion beam extraction position Will also grow. As described in FIG. 21, the distance between each of the beam orbits 78 where ion beams having different energies circulate and the entrance of the beam emission path 20 is different from each other for the ion beams of each energy shown in FIG. This is because the distance between the orbit 78 and the septum electromagnet 19 is different.

  The accelerator 4 in which the orbit concentric area and the orbit eccentric area are formed can stably circulate the ion beam of each energy along the respective beam orbits 78 by the respective characteristics shown in FIGS. 14 to 21. The ion beams having different energies which can be applied to the layers different in the divided depth of the affected part irradiated with the ion beam can be continuously emitted.

  The particle beam irradiation method using the particle beam irradiation apparatus will be described with reference to FIGS.

  Treatment plan data for each patient 56 who applies the ion beam to treat the affected area of cancer is created using the treatment planning device 73 before treatment. The treatment plan data includes the identification number of the patient, the number of layers of the affected area divided in the depth direction from the patient's body surface, the energy of the ion beam irradiated for each layer, the irradiation direction of the ion beam, and each layer. It includes data such as the irradiation position (spot position) and the irradiation amount of the ion beam for each irradiation position in each layer. The treatment plan data created by the treatment planning device 73 is stored in a database 72 which is a storage device.

  The CPU 67 reads treatment plan data regarding the patient 56 who is to be treated from the database 72 from the database 72 using the input patient identification information, and stores it in the memory 68. In the memory 68, according to the energy of the ion beam to be irradiated (for example, 70 MeV to 235 MeV), excitation current values supplied to the quadrupole electromagnets 46, 47, 49 and 50 of the beam transport system 13 and the deflection electromagnets 41 to 44, accelerator Positional information of each beam orbit where the ion beam of each energy orbits at the intermediate surface 77 in 4 and each of the magnetic poles 32A and 32B of the massless septum 12 when kicking out the ion beam orbiting each beam orbit The excitation current values supplied to the wound coils 33A, 33B are also stored.

  The CPU 67 functions as a control information creation device to treat the affected area of the patient 56, the treatment plan data, the excitation current value supplied to each electromagnet of the beam transport system 13, the position information of each beam orbit, and the massless septum 12. Control command information for controlling the electromagnets and massless septum 12 of the beam transport system 13 is created using the excitation current values supplied to the coils 33A and 33B.

  The procedure of each process shown in FIG. 23 is stored in the memory 68, and based on this procedure, the CPU 67 outputs control command information to each control device included in the accelerator / transport system control device 69 and the scan control device 70 respectively. Do.

  Excitation current is supplied to the annular coil and the trim coil (step S1). The coil current control device 94 having received the control command information from the CPU 67 controls the respective power supplies 37 and 57 in order to carry out the process of step S1. As described above, the excitation current is supplied from the power supplies 37 to the trim coils 8A to 8F to excite the magnetic poles 7A to 7F. Also, an excitation current is supplied from the power source 57 to the annular coils 11A and 11B, and the iron cores 14A and 14B are excited. As a result, the magnetic lines of force described above are generated in the iron cores 14A and 14B. The annular coil current and the trim coil current shown in FIG. 25 flow through the annular coils 11A and 11B and the trim coils 8A to 8F. The vacuum pump 25 is always driven, exhausts the air in the vacuum vessel 27 to the outside through the suction pipe 26, and maintains the vacuum in the vacuum vessel 27. The penetrating portions of the waveguides, the lead-out wires, and the operation members 16 and 16A of the return yokes 5A and 5B constituting the vacuum vessel 27 are sealed with sealing members to maintain airtightness.

  The ion source is activated (step S2). The accelerator / transport system controller 69 having received the control command information from the CPU 67 activates the ion source 3 and controls it.

  A high frequency voltage is applied to the high frequency acceleration electrode (step S3). The high frequency voltage control device 99 controls each high frequency power supply 36 based on the control command information from the CPU 67 to adjust the high frequency voltage applied to each of the high frequency accelerating electrodes 9A to 9D in order to carry out the process of step S3. . As a result, as described above, the high frequency voltage is applied to the high frequency accelerating electrodes 9A to 9D. The high frequency voltage of the frequency shown in FIG. 25 is applied to the high frequency accelerating electrodes 9A to 9D.

  A voltage is applied to the incident electrode (step S4). The entrance electrode control device 83 controls the power source 80 based on the control command information from the CPU 67 to apply a voltage to the entrance electrode 18 in order to carry out the process of step S4. When a voltage is applied to the incidence electrode 18, ions are incident on the ion incidence portion 109 formed in the beam circulation area 76 through the ion implantation port formed at the tip of the ion incidence tube 3A from the ion source 3 ( The protons) are bent in the horizontal direction by the incidence electrode 18, and accelerated at the connection portion of the high frequency accelerating electrode 9C and the high frequency accelerating electrode 9D located near the ion incident portion 109 and start to rotate in the counterclockwise direction.

  The ion beam is circulated in the accelerator until the energy increases to the set energy (step S5). The incident protons become ion beams, and in a state in which each of the magnetic poles 7A to 7F and the annular coils 11A and 11B are excited, first, the ion beam is 70 MeV by the high frequency accelerating electrodes 9C and 9D to which a high frequency voltage is applied. Accelerated to In each beam orbit having an energy of 70 MeV or less, the ion beam is accelerated four times as it travels around the beam orbit by these two high frequency acceleration electrodes. In the energy region exceeding 70 MeV, the high frequency accelerating electrodes 9A and 9B to which the high frequency voltage is applied also contribute to the acceleration of the ion beam, and as a result, the ion beam is accelerated to 220 MeV at the high frequency accelerating electrodes 9A to 9D. In each beam orbit with energy exceeding 70 MeV, the ion beam is accelerated eight times as it travels around the beam orbit by these four high frequency accelerating electrodes. The accelerated ion beam orbits the beam orbit 78 in the intermediate plane 77 in the accelerator 4, and the energy of this ion beam is increased to the set energy (for example, 250 MeV). At this time, at the position where the massless septum 12 is disposed, for example, those ion beams orbiting the beam orbits 78 for the respective 70 MeV to 250 MeV ion beams shown in FIG. It passes through a beam passage 35 formed between the 12 opposing magnetic poles 32A and 32B.

  An ion beam having an energy of 70 MeV or more is applied to the affected area of the patient 56 for treatment. The ion beam having an energy of 70 MeV or more is an ion beam having the lowest energy among the ion beams irradiated to the affected area to be irradiated.

  The ion beam orbiting each beam orbit is measured (step S6). The beam current measuring unit control device 84 controls the moving device 17A based on the control command information from the CPU 67 to carry out the process of step S6. By this control, the moving device 17A is driven to move the operation member 16A. Usually, the beam current measuring unit 15 drawn to a position between the annular coil 11A and the annular coil 11B reaches the beam passage 35 through the through hole 31D of the connecting portion 31C by the movement of the operation member 16A, and the intermediate surface 77 , Move along the alternate long and short dash line X toward the incident electrode 18. The beam current measurement unit 15 moves the beam orbits 78 (for example, the ion beams of 250 MeV shown in FIG. 10 orbit the ion orbits of 70 to 70 MeV) while moving toward the incident electrode 18. The beam current of the ion beam orbiting the beam orbit 78) is measured for each of the beam orbits 78). The value of each beam current measured by the beam current measurement unit 15 corresponds to the energy of the ion beam circulating in each beam orbit 78. Each energy information corresponding to the measured value of each beam current is transmitted to the beam current measurement unit controller 84. The position of the beam current measuring unit 15 directed to the incidence electrode 18 is detected by the position detector 39 for each beam orbit 78. The position information of the beam current measurement unit 15 detected by the position detector 39, that is, the position information of the beam orbit 78 in the radial direction of the annular coil is also transmitted to the beam current measurement unit controller 84. The beam current measuring unit controller 84 stores the energy information corresponding to each measured beam current value and the position information of each beam orbit 78 in the memory 107 of the accelerator / transport system controller 69 in association with each other. Do. An example of the information obtained by associating each energy information with each beam orbit 78 is shown in FIG.

  It is determined whether the beam orbit is formed at a predetermined position (step S23). The coil current control unit 94 determines whether each beam orbit 78 is formed at a predetermined position on the intermediate surface 77 based on the position information of each beam orbit 78 read from the memory 107.

  The excitation current supplied to the trim coil is adjusted (step S24). When the position of at least one beam orbit 78 among the beam orbits 78 is deviated from the predetermined position, the determination result in step S23 is “No”. At this time, the coil current control device 94 controls the power supply 37 connected to each of the trim coils 8A to 8F installed at the magnetic poles 7A to 7F, and the beam orbits 78 deviated from the predetermined position are at predetermined positions. The excitation current supplied to each of the trim coils 8A to 8F is adjusted so as to be formed into. Such adjustment of the excitation current corrects the position of the beam orbit.

  Then, each process of step S6 and S23 is implemented. When the determination result of step S23 is "No", each process of step S24, S6 and S23 is repeated until the determination result of step S23 becomes "Yes". When all the beam orbits 78 formed on the intermediate surface 77 are formed at respective predetermined positions, the determination result of step S23 is "Yes", and the process of step S7 is performed.

  The amount of excitation of each of the septum electromagnet and each of the beam transport system electromagnets is adjusted (step S7). The electromagnet control device 85 controls the power supply 82 based on the control command information from the CPU 67 to carry out the process of step S7, and the energy of the ion beam emitted from the excitation current supplied to the septum electromagnet 19 (for example, Adjust the excitation current corresponding to 250 MeV). The septum electromagnet 19 is excited by this exciting current. Further, the electromagnet control device 85 controls another power source (not shown) based on the control command information, and the quadrupole electromagnets 46, 47, 49 and 50 of the beam transport system 13 and the deflection electromagnets 41 to 44 respectively. The excitation current supplied to is adjusted to the excitation current corresponding to the energy (for example, 250 MeV) of the emitted ion beam. The excitation current excites the quadrupole electromagnets and the deflection electromagnets. The septum electromagnet 19 and each of the electromagnets provided in the beam transport system 13 are excited in a state capable of transporting the 250 MeV ion beam to the emitting device 7.

  The position of the magnetic pole of the massless septum is adjusted (step S8). In order to carry out the process of step S8, the massless septum control device 86 controls the moving device 17 based on the control command information from the CPU 67, and moves the operation member 16 using the moving device 17 to perform mass control. In the radial direction of the vacuum vessel 27, along the alternate long and short dash line X in the radial direction of the vacuum vessel 27, from the position 180 ° opposite to the entrance of the beam outgoing path 20 toward the incident electrode 18 with the central axis C of the vacuum vessel 27 as a base point. Be moved. The massless septum 12 can be moved by the moving device 17 within a range of, for example, about 10 mm. Movement within this range is performed to finely adjust the positioning of the pair of opposing magnetic poles 32A, 32B. Due to the movement of the massless septum 12, an ion beam of 250 MeV, for example, is generated in a region where the distance between the beam orbits 78 adjacent to the entrance of the beam outgoing path 20 180 ° opposite to the central axis C is large. The angle on the incident electrode 18 side of each of the pair of magnetic poles 32A and 32B to be excited in accordance with the orbiting beam orbit 78 is aligned with the orbiting beam 78. At this time, the position of the massless septum 12 in the vacuum vessel 27 is the position of the massless septum 12 shown on the leftmost side shown in FIG.

  The magnetic pole of the massless septum is excited (step S9). After the corresponding pair of magnetic poles 32A, 32B is aligned with the beam orbit 78 where the 250 MeV ion beam circulates, the massless septum controller 86 executes control command information from the CPU 67 to carry out the process of step S9. Control the power supply 40 based on Furthermore, the massless septum control device 86 controls the switch to connect each of the wires 23A and 23B connected to each of the coils 33A and 33B wound around each of the magnetic poles 32A and 32B to be excited to the power supply 40. Connecting. The excitation current from the power source 40 is supplied to the coils 33A and 33B, respectively, and the pair of magnetic poles 32A and 32B to be excited opposite to each other is excited. By this excitation, magnetic lines of force are generated in the closed magnetic circuit of the excited magnetic poles 32A and 32B, the iron core 31B, the connecting part 31C, the iron core 31A and the magnetic pole 32A. Magnetic lines of force from the magnetic pole 32A to the magnetic pole 32B cross the beam path 35 formed between the magnetic poles and through which the ion beam passes. Due to the action of the magnetic field lines, a 250 MeV ion beam is kicked out of the beam orbit 78, which is around the ion beam, and is separated from the beam orbit 78 toward the entrance of the beam emission path 20 formed in the septum electromagnet 19. Move.

  Eventually, the kicked-out 250 MeV ion beam is emitted to the beam path 48 of the beam transport system 13 through the beam emission path 20 by the action of the excited septum electromagnet 19. The ion beam is guided to the irradiation device 7 through the beam path 48 and emitted from the irradiation device 7. At this time, the patient 56 is not lying on the couch 55.

  The emission from the accelerator of the ion beam is confirmed (step S10). A beam position monitor 53 provided in the irradiation device 7 detects the position of the ion beam passing through the irradiation device 7. Position information of the detected ion beam is input from the beam position monitor 53 to the ion beam confirmation device 87. When the position information of the ion beam is input, the ion beam confirmation device 87 determines that the ion beam is emitted from the accelerator 4 and outputs the determination result to a display device (not shown). The operator confirms the emission of the ion beam by viewing the determination result displayed on the display device.

  This is the end of the description of the steps for extracting the ion beam from the accelerator.

  Next, based on the procedure shown in FIG. 26, each step of irradiating each ion beam with different energy in the layer of the affected part of the patient in the particle beam irradiation method will be described.

  After the patient 56 lies on the treatment table 55, the treatment table 55 is moved to position the affected area on the extension of the beam axis of the irradiation device 7.

  The rotating gantry is rotated to set the beam axis of the irradiation apparatus in the direction of ion beam irradiation to the affected area (beam irradiation target) (step S11). The affected area of the patient 56 to be treated by ion beam irradiation is a beam irradiation target. The rotation control device 88 controls the rotation device (not shown) of the rotating gantry 6 based on the control command information from the CPU 67 to carry out the process of step S11. The rotation device is driven, and the rotation gantry 6 is set until the beam axis through which the ion beam of the irradiation device 7 passes is set in this irradiation direction based on the information on the irradiation direction of the ion beam included in the aforementioned treatment plan data It is rotated about the rotation axis 45. When the beam axis of the irradiation device 7 coincides with this irradiation direction, the rotation of the rotating gantry 6 is stopped.

  One layer in a beam irradiation target for irradiating an ion beam is set (step S12). The irradiation position control device 89 sets one layer to which the ion beam in the affected area is irradiated based on the control command information from the CPU 67. In the setting of this layer by the irradiation position control device 89, the layer at the deepest position is set based on the information of the plurality of layers obtained by dividing the affected area, which is the treatment plan data stored in the memory 70. Furthermore, the irradiation position control device 89 searches the memory 70 for information (for example, 220 MeV) of the energy of the ion beam irradiated to the set layer. The irradiation position control unit 89 outputs the energy information of the retrieved ion beam to the massless septum control unit 86.

  The magnetic pole of the massless septum is positioned (step S13). Of the plurality of magnetic poles 32A and 32B formed on the massless septum 12, positioning is performed on the ion beam orbital orbit 78 of 220 MeV corresponding to the energy (for example, 220 MeV) of the ion beam irradiated to the aforementioned set layer. The other pair of opposing magnetic poles 32A and 32B are positioned closer to the incidence electrode 18 than the pair of magnetic poles 32A and 32B positioned on the beam trajectory 78 in which the 250 MeV ion beam circulates in step S8. Magnetic poles 32A and 32B. The massless septum control device 86 inputs the information of the layer set by the irradiation position control device 89 from the irradiation position control device 89. The massless septum controller 86 detects the energy (220 MeV) of the ion beam irradiated to the set layer input from the irradiation position controller 89 and the position of the beam orbit 78 associated with the energy stored in the memory 107. Based on the information (the position information of the beam current measurement unit 15 detected by the position detection device 39), positioning is performed on the beam circulation orbit 78 of the 220 MeV ion beam among the plurality of pairs of magnetic poles 32A and 32B of the massless septum 12. The pair of magnetic poles 32A and 32B to be excited is specified. Further, the massless septum control device 86 sets the angle on the incident electrode 18 side of each of the pair of magnetic poles 32A and 32B specified based on the position information of the beam orbit 78 stored in the memory 107 to ions of 220 MeV. The amount of movement of the massless septum 12 in the radial direction of the annular coil for positioning in the beam trajectory 78 of the beam is determined.

  The massless septum control device 86 controls the moving device 17 based on the determined movement amount of the massless septum 12 to move the massless septum 12 toward the incident electrode 18. By this movement, the angle on the side of the incident electrode 18 of each of the identified magnetic poles 32A and 32B to be excited adjacent to each other on the opposite side of the entrance of the beam emission path 20 with respect to the central axis C is 180 °. In the region where the distance between the orbits 78 is wide, the ion beam of 220 MeV is positioned at the orbit 78 around which the ion beam orbits. The movement amount of the massless septum 12 due to the positioning of the pair of magnetic poles 32A and 32B identified can be confirmed based on the position data of the massless septum 12 measured by the position detector 38. The process of step S13 is substantially the same as the process of step S8 described above.

  The magnetic pole of the massless septum is excited (step S14). After the positioning of the magnetic pole in step S13 is completed, the massless septum control device 86 controls the switch based on the information of the specified pair of magnetic poles 32A and 32B, and the other excitation to be positioned in step S13 is to be excited. The wires 23A and 23B connected to the coils 33A and 33B wound around the magnetic poles 32A and 32B, respectively, are connected to the power supply 40. Then, the massless septum control device 86 controls the power supply 40 based on the control command information from the CPU 67, and the kicking necessary for causing the ion beam of 220 MeV shown in FIG. The power supply 40 is controlled to output an excitation current that can obtain an amount. The excitation current is supplied to each of the coils 33A and 33B wound around the pair of opposing magnetic poles 32A and 32B to be excited which are positioned as described above, and the magnetic poles 32A and 32B to be excited are excited. . The process of step S13 is substantially the same as the process of step S8 described above.

  The amount of excitation of each of the septum electromagnet and each of the beam transport system electromagnets is adjusted (step S7). The electromagnet control device 85 inputs the information of the layer set by the irradiation position control device 89 from the irradiation position control device 89. The electromagnet control device 85 controls the power supply 82 as described above based on the energy information (for example, 220 MeV) of the ion beam irradiated to the set layer, and the septum electromagnet 19 is emitted from the ion beam It excites with the excitation current corresponding to 220 MeV. Further, as described above, the quadrupole electromagnets 46, 47, 49 and 50 and the deflection electromagnets 41 to 44 of the beam transport system 13 are also excited by the excitation current corresponding to 220 MeV. At this time, the excitation amount of each of the septum electromagnet 19 and the electromagnets provided in the beam transport system 13 is the second lowest excitation amount from the left in the lowermost characteristic of FIG.

  The scanning electromagnet is controlled to set the irradiation position of the ion beam in the set layer (step S15). The irradiation position control device 89 receives the adjustment completion signal of the excitation amount of each electromagnet from the electromagnet control device 85, and based on the information of the irradiation position in the set layer included in the treatment plan data, Each of the scanning electromagnets 51 and 52 generates a deflection magnetic field so as to control the excitation current supplied to each of 52 and to irradiate the ion beam to the target irradiation position. The deflection magnetic field generated by the scanning electromagnet 51 controls the position of the ion beam emitted from the accelerator 4 in the process of step S16 described later in the y direction. The deflection magnetic field generated by the scanning electromagnet 52 controls the position of the ion beam emitted from the accelerator 4 in the x direction orthogonal to the y direction.

  In step S15, when the irradiation position control device 89 determines that the respective excitation currents to the scanning electromagnets 51 and 52 are controlled such that the ion beam reaches the target irradiation position of the ion beam, a beam irradiation start signal Output

  A voltage is applied to the incident electrode (step S16). When the beam irradiation start signal is input from the irradiation position control device 89, the incidence electrode control device 83 controls the power supply 80 and applies a voltage to the incidence electrode 18 as in step S4. Ions incident on the beam circulation area 76 from the ion source 3 through the ion injection tube 3A are bent in the horizontal direction by the incident electrode 18 and circulate in the intermediate plane 77, and the high frequency accelerating electrode 9A to which a high frequency voltage is applied Accelerated by 9D. The ion beam orbiting along the beam orbit 78 in which the ion beam of 220 MeV orbits enters the beam path 35 formed between the pair of magnetic poles 32A and 32B excited in step S14. The ion beam entering the beam passage 35 is kicked out of the beam orbit 78, which is orbited by the action of the pair of excited magnetic poles 32A and 32B. That is, the ion beam is separated from the beam orbit 78. Thereafter, the ion beam moves away from the beam orbit 78 toward the entrance of the beam emission path 20, passes the beam emission path 20 by the action of the septum electromagnet 19, and is emitted from the accelerator 4 to the beam path 48. Ru. The ion beam reaching the irradiation device 7 is irradiated to a target irradiation position in the layer set by the action of the scanning electromagnets 51 and 52.

  The position of the ion beam irradiated to the target irradiation position is measured by the beam monitor 53, and based on the measured position, it is confirmed that the ion beam is irradiated to the target irradiation position.

  It is determined whether the irradiation dose at the irradiation position matches the target dose (step S17). The irradiation dose to the target irradiation position is measured by the dose monitor 54. The measured irradiation dose is input to the dose determination device 91. The dose determination device 91 determines whether the irradiation dose irradiated to the target irradiation position and measured reaches the target irradiation dose. When the measured irradiation dose does not match the target irradiation dose, the determination in step S17 is "No", and the steps of step S16 and step S17 are repeated, and the measured irradiation dose is the target irradiation. The irradiation of the ion beam to the target irradiation position is continued until the dose matches. When the measured irradiation dose matches the target irradiation dose (when the determination in step S17 is “Yes”), the dose determination device 91 outputs a beam emission stop signal to the incidence electrode control device 83.

  The application of the voltage to the incidence electrode is stopped (step S18). When receiving the beam emission stop signal from the dose determination unit 91, the incidence electrode control unit 83 controls the power supply 80 to stop the application of the voltage from the power supply 80 to the incidence electrode 18. As a result, the incidence of protons from the ion source 3 to the beam circulation area 76 is stopped, and the emission of the ion beam from the accelerator 4 to the beam path 48 is stopped. That is, the irradiation of the ion beam to the affected area is stopped.

  It is determined whether the irradiation of the ion beam into the set layer is completed (step S19). When the irradiation of the ion beam to a certain irradiation position is completed, the layer determination device 92 determines whether the irradiation of the ion beam into the set layer is ended. When the determination result is "No", that is, when the irradiation of the ion beam into the set layer is not completed, the steps S15 to S19 are repeatedly performed. In the repeated step S15, the excitation current supplied to each of the scanning electromagnets 51 and 52 is controlled so that the ion beam is irradiated to the target other irradiation position in the set layer.

  The ion beam is irradiated to the other irradiation position in step S16, and when the determination in step S17 is "Yes", the application of the voltage to the incidence electrode 18 is stopped in step S17.

  When the determination in step S19 is "Yes", it is determined whether the irradiation of the ion beam to all the layers is completed (step S20). The layer determination unit 92 determines whether the irradiation of the ion beam to all the layers is completed. Since the layer to which the ion beam irradiation has not been performed remains, the determination in step S20 is "No", and the steps S12 to S14, S7, and S15 to S20 are repeated and sequentially performed. In step S12, the layer at the second deepest position is set. The energy required for the ion beam irradiated to this layer is 219 MeV.

  In the repeated step S13, the angle on the side of the incident electrode 18 of each of the other magnetic poles 32A and 32B adjusted to the beam orbit 78 where the above-mentioned 220 MeV ion beam moves is the same as in the previous step S13. , And is positioned in a beam orbit 78 of an ion beam of 219 MeV. The amount of movement of the massless septum 12 at this time is larger than that in the case where the magnetic poles 32A and 32B are positioned on the beam circulation orbit 78 in which the ion beam of 220 MeV moves. These other magnetic poles 32A and 32B are excited in step S14.

  In steps S15 and S16, when a voltage is applied to the incidence electrode 18, the ion beam orbits along each beam orbit 78, and an ion beam of 219 MeV is generated by the action of the other magnetic poles 32A and 32B excited The 219 MeV ion beam is kicked out of the orbiting beam orbit 78. The kicked-out ion beam is irradiated from the irradiation device 7 to the irradiation position of the second deepest layer in the affected area. When the determination in step S17 becomes "Yes", step S18 is executed to stop the irradiation of the ion beam to the irradiation position.

  When the determination in step S19 is "No", the processes in steps S15 to S19 are repeated until the determination in step S19 is "Yes". When the determination in step S19 is "No", the processes in steps S12 to S14, S7 and S15 to S20 are repeatedly and sequentially executed until the determination in step S20 is "Yes". When each step of steps S12 to S14, S7 and S15 to S20 is repeated, a shallower layer is set in step S12, and the energy of the ion beam reaching this layer is sequentially lowered (for example, starting from 220 MeV, every 1 MeV) Reduce energy). In steps S13 and S14, the opposing magnetic poles 32A and 32B of the massless septum 12 are positioned on the beam orbiting orbit 78 in which the low energy ion beams circulate, and thereafter, these magnetic poles are excited. . When emitting 180 MeV and 160 MeV ion beams from the accelerator 4, another pair of magnetic poles 32A and 32B excited when emitting 220 MeV and 200 MeV ion beams are located next to each other on the incident electrode 18 side. The pair of magnetic poles 32A and 32B are excited in step S14. However, when the ion beam of 160 MeV is emitted, the movement amount of the massless septum 12 at the time of positioning of the magnetic pole in step 13 is larger than that when the ion beam of 180 MeV is emitted.

  When the determination in step S20 is "Yes", the irradiation of the ion beam to the affected area is completed (step S21).

  Thus, the treatment of the affected area of the patient 56 by the ion beam irradiation is completed.

  In the present embodiment, the iron cores 14A and 14B have a circular shape suitable for forming the outermost beam orbit at the intermediate surface 77, but may be implemented with other shapes. Further, although the annular coils 11A and 11B are also circular, they may have other shapes, for example, a clover shape surrounding each magnetic pole formed on the base portion of the return yoke.

  In a general cyclotron, the ion beam can be extracted only from the beam orbit of the ion beam having the highest energy formed at the outermost periphery. However, according to the present embodiment, a plurality of beam trajectories 78 having different energies are formed at the entrance of the septum electromagnet 19 and the beam emission path 20 by forming a beam orbit eccentric region in the accelerator outer peripheral portion where the beam trajectories become narrow. The beam orbit 78 is different from not only the beam orbit 78 in which the highest energy ion beam located at the outermost periphery orbits but also a plurality of beam orbits 78 formed inside the beam orbit 76. Each ion beam having energy can be selectively extracted at any time. Therefore, according to the present embodiment, the ion beam with different energy can be efficiently emitted from the accelerator 4.

  According to this embodiment, a plurality of annular beam orbits 78 whose centers are offset from each other are densely incident between the entrance electrode 18 or the ion injection port or the ion entrance portion 109 and the entrance of the beam exit path 20. Orbital eccentricity area in which the distance between the annular beam orbits 78 is 180 ° opposite to the entrance of the beam exit path 20 with respect to the entrance point of the beam exit path 20 is the entrance electrode 18 (or Or, since it is formed on the intermediate surface 77 which exists in the beam circulation area 76 and the beam circulation track 78 is formed around the ion incident part 109), the incidence electrode 18 in the beam circulation eccentric area is formed. On the opposite side of the entrance of the beam outgoing path 20, the distance between the beam orbits 78 of the respective ion beams having different energies is wide. Thus, each ion beam of different energy can be efficiently removed from the corresponding beam orbit 78. Therefore, each ion beam having different energy can be efficiently emitted to the beam path 48 of the beam transport system 13 through the beam emission path 20 formed in the septum electromagnet 19 of the accelerator 4. Furthermore, in the present embodiment, each ion beam with different energy can be emitted from the accelerator 4 continuously.

  In this embodiment, since an orbital concentric area in which a plurality of concentric annular beam orbits 78 around the incidence electrode 18 are formed is formed inside the orbital eccentric area at the intermediate surface 77, the ion beam is The degree of concentration of the beam orbit 78 near the entrance of the outgoing beam outgoing path 20 is reduced, and as a result, the magnetic field gradient near the entrance becomes smaller. The ion beams having different energies can more stably orbit the corresponding beam orbit 78.

  Since the ion incident part 109 (or the incident electrode 18 or the ion injection port) is disposed at a position different from the center of gravity of the annular coil in the radial direction, it is arranged around the ion incident part (or the incident electrode 18 or the ion injection port) The distance between adjacent ones of the plurality of annular beam orbits 78 formed is closer to the ion incident portion than the region on the inlet side of the beam outgoing path 20 from the ion incident portion 109 (or the incident electrode 18 or the ion implantation port) From the point (or the incidence electrode 18 or the ion implantation port), the region on the opposite side of the entrance of the beam emission path 20 becomes wider. For this reason, it is possible to easily separate the ion beam from the beam orbit 78 in a region opposite to the entrance of the beam exit path 20 where the distance between adjacent beam orbits 78 becomes wider, and the beam orbit of each ring It is possible to efficiently emit ion beams of different energies traveling around the orbit 78.

  Since the ion incident part 109 (or the incident electrode 18 or the ion injection port) is disposed at a position different from the center of the iron core in the radial direction, around the ion incident part 109 (or the incident electrode 18 or the ion injection port) The distance between adjacent ones of the plurality of annular beam orbits 78 formed is closer to the ion incident portion 109 than the region on the entrance side of the beam emission path from the ion incident portion 109 (or the incident electrode 18 or the ion implantation port). From the point (or the incidence electrode 18 or the ion implantation port), the region on the opposite side of the entrance of the beam emission path 20 becomes wider. For this reason, it is possible to easily separate the ion beam from the beam orbit 78 in a region opposite to the entrance of the beam exit path 20 where the distance between adjacent beam orbits 78 becomes wider, and the beam orbit of each ring It is possible to efficiently emit ion beams of different energies traveling around the orbit 78.

  Since the tips of the portions of the high frequency accelerating electrodes 9C and 9D extending from the position of the inner surface toward the inner side of the annular coil are disposed at positions different from the center of gravity of the annular coil in the radial direction The distance between adjacent ones of the plurality of annular beam orbits 78 formed around the position where the tip of each of the electrodes 9C and 9D is disposed is determined by the ion incident portion 109 (or the incident electrode 18 or the ion injection The region on the opposite side of the entrance of the beam exit path 20 is wider than the area on the entrance side of the beam exit path 20 from the entrance) with respect to the ion entrance 109 (or the incidence electrode 18 or ion implantation port). For this reason, it is possible to easily separate the ion beam from the beam orbit 78 in a region opposite to the entrance of the beam exit path 20 where the distance between adjacent beam orbits 78 becomes wider, and the beam orbit of each ring It is possible to efficiently emit ion beams of different energies traveling around the orbit 78.

  The magnetic poles (convex portions) 7A to 7F are disposed to extend radially inward from the outer periphery of the iron core toward positions different from the center of gravity of the iron core in the radial direction, and thus the respective tip portions of the magnetic poles 7A to 7F The adjacent mutual spacings of the plurality of annular beam orbits 78 formed around positions radially different from the center of gravity of the iron core on which the The region on the opposite side of the entrance of the beam exit path 20 is wider than the area on the entrance side of the beam exit path 20 from the entrance) with respect to the ion entrance 109 (or the incidence electrode 18 or ion implantation port). For this reason, the ion beam can be easily separated from the beam orbit 78 in the region opposite to the entrance of the beam outgoing path 2 where the distance between adjacent beam orbits 78 adjacent to each other becomes wider, and each annular beam orbit It is possible to efficiently emit ion beams of different energies traveling around the orbit 78.

  According to the present embodiment, since the plurality of beam orbits 78 are focused at the entrance of the beam outgoing path 20, each ion beam of different energy decoupled from the respective beam orbits 78 can be It becomes easy to be incident on the inlet, and each ion beam with different energy can be emitted efficiently.

  According to this embodiment, since the center of the annular beam orbit 78 formed by the magnetic poles 7A to 7F is different from the position of the center of gravity of the annular coil, the ion incident portion 109 (or the incident electrode 18 or ion injection The distance between adjacent ones of the plurality of annular beam orbits 78 formed around the entrance is wider in the central area of the annular beam orbit 78 than the area on the entrance side of the beam exit path 20. For this reason, it is possible to easily separate the ion beam from the beam orbit 78 in the region on the center side of the beam orbit 78 where the distance between the beam orbits 78 adjacent to each other widens. Can be efficiently emitted.

  According to the present embodiment, the region with the highest magnetic field strength in the intermediate surface 77 is the ion incident portion 109 (or the incident electrode 18 or the ion implantation port) than the beam orbits 78 at the outermost periphery in the first magnetic field Since it is formed on the side, it is possible to efficiently emit ion beams different in energy, and further, the beam orbit located at the outer peripheral portion among the plurality of annular beam orbits 78 formed on the intermediate surface 77 The stability of the circulating ion beam is improved.

  According to the present embodiment, each of the pair of iron cores 14A and 14B has the ion incident portion 109 (or the incident electrode 18 or the ion implantation port) around the ion incident portion 109 (or the incident electrode 18 or the ion implantation port) The magnetic poles 7A to 7F are formed so that the tips of the magnetic poles 7A to 7F face the ion incident portion 109 (or the incident electrode 18 or the ion injection port) radially from the Recesses 29A to 29F radially extending from the ion incident portion 109 (or the incident electrode 18 or the ion injection port) are formed around the inlet), and the ion incident portion 109 (or the incident electrode 18 or the ion injection port) The magnetic poles and the recesses are alternately arranged in the periphery of the ring coils 11A and 11B in the iron cores 14A and 14B. Since surrounds each arranged poles 7A~7F and recesses 29a to 29f, it is possible to incidence of ions into the beam circulating region 76 through ion injection pipe 3A stable.

  In this embodiment, since the entrance of the beam emission path 20 is opened in the recess 29D (second recess), the ion beam released from the annular beam orbit 78 can be easily incident on the entrance of the beam emission path 20. As a result, it is possible to efficiently emit ion beams of different energies which circulate around each annular beam orbit 78. This is because the respective annular beam orbits 78 formed in the orbit eccentric region are focused on the entrance side of the beam exit path 20 in the recess 29A.

  In the present embodiment, each of the magnetic poles 7A to 7F has a bending point, and a portion from the bending point of each of the magnetic poles 7A to 7F to the end surface facing the inner surface of the annular coil is bent toward the recess 29A. Thus, a beam eccentric region in which a plurality of eccentric beam orbits 78 exist is formed, the distance between the beam orbits is increased, and each ion beam of different energies orbits each annular beam orbit 78 It can emit efficiently.

  In the present embodiment, since the beam current measuring device 98 is disposed in the recess 29A, the energy of each ion beam orbiting each beam orbit 78 and each beam orbit 78 are measured by the beam current measuring device 98. It is possible to obtain information on the position in the radial direction of the toroidal coil. Using the energy information of each ion beam and the position information of each beam orbit 78, the position information of the beam orbit 78 corresponding to the energy of the ion beam irradiated to the set layer included in the affected area can be obtained This position information can identify the pair of opposing magnetic poles 32A, 32B to be excited of the massless septum 12 and irradiate the set layer with the pair of opposing magnetic poles 32A, 32 to be excited. It can be precisely positioned on the beam orbit 78 in which the ion beam of the desired energy is circulated.

  Further, the beam current measurement unit 15 of the beam current measurement device 98 is moved along the intermediate surface 77 in the recess 29A toward the ion incident portion 109 (or the incident electrode 18 or the ion implantation port) using the moving device 17A. Since the beam travels, energy information of each ion beam with respect to each beam orbit 78 and position information of each beam orbit 78 can be obtained in a wide range.

  When the position of the beam orbit 78 measured by the beam current measuring device 98 disposed in the recess 29A does not exist at a predetermined position, the excitation supplied to the trim coils 8A to 8F respectively attached to the magnetic poles 7A to 7F Since the current is adjusted by the coil current controller 94, even if a beam orbit 78 not existing at a predetermined position is formed, the beam orbit 78 can be formed at a predetermined position.

  In the present embodiment, as described above, in each of the pair of iron cores 14A and 14B, the tip is opposed to the incident electrode 18 in each plane on the both sides of the dashed dotted line X in a plane perpendicular to the central axis C. Between the magnet 7C and the magnetic pole 7E adjacent to the high frequency accelerating electrode 9C in the circumferential direction of the vacuum vessel 27, the magnet 7D adjacent to the high frequency accelerating electrode 9D in the circumferential direction of the vacuum vessel 27 with the tip facing the incident electrode 18 And the magnetic pole 7F, a portion from the bending points 24M, 24N of the high frequency accelerating electrode 9C to the end face of the high frequency accelerating electrode 9C facing the annular coil 11A or 11B, and , 24N to the end face of the high-frequency accelerating electrode 9C facing the annular coil 11A or 11B is bent toward the recess 29A. Runode, each ion beam circulating each beam orbit 78 that exists between the incident electrode 18 near the beam orbit 78 and the annular coil 11A or 11B near the beam orbit 78 can be easily accelerated. Furthermore, in the present embodiment, the high frequency accelerating electrodes 9A and 9B are disposed between the magnetic pole 7A and the magnetic pole 7C and between the magnetic pole 7B and the magnetic pole 7D, respectively, Since they are respectively disposed between the opposing end faces, the ion beams which respectively travel around the beam orbits 78 of the ion beam having high energy can be easily accelerated.

  In the present embodiment, the beam current measurement unit 15 is disposed in the recess 29A in the intermediate surface 77, and the beam current measurement unit 15 is moved by the moving device 17 along the dashed dotted line X in the intermediate surface 77. Since the position of the beam current measurement unit 15 moved by the position in the intermediate plane 77 is detected, as described above, the beam current value in each beam orbit 78 and the positions of these beam orbits 78 are accurately detected. be able to.

  Since the massless septum 12 is disposed in the recess 29A of each of the pair of iron cores 14A and 14B, the massless septum 12 can be easily disposed between the iron core 14A and the iron core 14B.

  Since the massless septum 12 is disposed in the recess 29A, the massless septum 12 is located at a position where the mutual spacings of the beam orbits 78 within the beam orbit eccentricity are increased. The respective ion beams having different energies can be efficiently separated from the respective beam orbits 78. Thereby, each ion beam from which energy differs can be efficiently radiate | emitted from the accelerator 4. FIG.

  Since the massless septum 12 has a plurality of pairs of opposing magnetic poles 32A and 32B, it should be positioned and excited in the beam orbit 78 based on the energy of the ion beam irradiated to the set layer of the affected area. The pair of magnetic poles 32A, 32B can be easily identified.

  Since the moving device 17 for moving the massless septum 12 in the radial direction of the annular coil is provided, the energy to be applied to the set layer of the affected area is the pair of magnetic poles 32A, 32B of the massless septum 12 to be excited. An adjustment of the positioning to the beam orbit 78 around which the ion beam having. Therefore, positioning of the pair of magnetic poles 32A and 32B on the corresponding beam orbits 78 can be performed with high accuracy.

  A particle beam irradiation apparatus using a cyclotron is provided with a degrader having a plurality of metal plates of different thicknesses in a beam transport system in order to change the energy of an ion beam to be irradiated to an affected area. On the other hand, in the particle beam irradiation apparatus 1 of the present embodiment, as described above, the ion beam with different energy can be emitted from the accelerator 4, and the degrader becomes unnecessary. Or, its use can be significantly reduced. For this reason, in the particle beam irradiation apparatus 1, the beam size of the ion beam is increased by the degrader, the number of ions is reduced by scattering of some ions when transmitting through the metal plate of the degrader, and activation of the degrader is caused. It is possible to prevent the increase of radioactive waste.

  In the present embodiment, in order to maintain a vacuum in the beam circulation area 76 in which the ion beam circulates, a pair of iron cores 14A and iron cores 14B are mutually opposed and coupled to form a vacuum vessel 27. For this reason, the accelerator 4 used in the present embodiment is smaller than the accelerator configured by arranging a vacuum vessel between the iron core 14 and the iron core 14B facing each other as in Examples 8 and 9 described later. Can be

  In this embodiment, as described above, in the beam circulation orbit 78 in which the low energy ion beam (ion beam of 70 MeV or less) circulates, the ion beam is accelerated by 9C and 9D with two high frequency acceleration electrodes. In addition, the eccentricity of the beam orbit 78 requires stable and fine orbit control, and high energy requires high rf acceleration voltage or long acceleration time for further acceleration, high energy ions The ion beam is accelerated by four high-frequency accelerating electrodes 9A to 9D in a beam orbit 78 in which the beam (ion beam exceeding 70 MeV) orbits.

  The number of high frequency accelerating electrodes disposed between the bending point of the magnetic pole and the inner surface of the annular coil and the number of high frequency accelerating electrodes extending from the ion implantation port to the inner surface of the annular coil are one or three or more, The functions described above can be exhibited. However, in order to form the above-described orbital eccentric region on the intermediate surface 77 which is the orbital surface in the beam circulation region 76, the high frequency acceleration electrodes 9A and 9C of the high frequency acceleration electrodes 9A to 9D The symmetry of the arrangement and the shape of the high frequency accelerating electrodes 9B and 9D with respect to a straight line (dotted dotted line X) connecting the entrance of the beam emission path 20 makes it easy to obtain the stability of the circulating ion beam.

  The iron cores 14A, 14B are circular in the horizontal direction, and generally the center means the structural center of the accelerator 4. Also, the annular coils 11A and 11B are circular main coils, and generally the center and the center of gravity also mean the structural center of the accelerator 4. Furthermore, in the accelerator 4 of the present embodiment, the above-described ion incident part is disposed at a position different from the center of the iron core and the center of gravity of the annular coil, and is disposed at a position shifted to the entrance side of the beam emission path 20.

  In the case of a conventional cyclotron, since the beam orbit is formed concentrically starting from the structural center of the accelerator, ions are incident on the structural center of the accelerator. Strictly speaking, ions are not incident on the center point itself but on the innermost beam orbit. Assuming that the region inside the innermost beam circulation orbit where ions are incident and guide this ion to the innermost beam circulation orbit is defined as an ion incident part, in the case of an ordinary cyclotron, this ion incidence The unit is located at the structural center of the accelerator. On the other hand, in the accelerator 4 used in the present embodiment, the ion incident part is disposed at a position different from both the center of the iron core and the center of gravity of the annular coil, and is disposed at a position shifted to the entrance side of the beam emission path 20 Ru.

  The particle beam irradiation apparatus according to the second embodiment which is another preferred embodiment of the present invention will be described below with reference to FIG.

  The particle beam irradiation apparatus 1A of the present embodiment includes an accelerator 4A, and has a configuration in which the accelerator 4 is replaced with an accelerator 4A in the particle beam irradiation apparatus 1 of the first embodiment. The other configuration of the particle beam irradiation apparatus 1A is the same as that of the particle beam irradiation apparatus 1.

  The accelerator 4A has a vacuum vessel 27 including return yokes 5A and 5B. These return yokes 5A, 5B are substantially the same as the return yokes 5A, 5B of the first embodiment. The return yoke 5B used for the accelerator 4A will be described. The return yoke 5B also has six magnetic poles 7A to 7F and four high frequency acceleration electrodes 9A to 9D to form six concave portions 29A to 29F. The magnetic poles 7A to 7F and the high frequency acceleration electrodes 9A to 9D are disposed inside the annular coil 11B. As in the case of the accelerator 4, one of the recesses 29A to 29F is disposed between the magnetic poles 7A to 7F. The arrangement of the high frequency accelerating electrodes 9A to 9D in the accelerator 4A is the same as the arrangement of the high frequency accelerating electrodes 9A to 9D in the accelerator 4.

  In the accelerator 4A, the ion injection port and the incidence electrode 18 are disposed in a state of being moved to the entrance side of the beam emission path 20 with respect to the return yoke 5B of the accelerator 4. With the movement of the incidence electrode 18 to the entrance side of the beam emission path 20, the ion incidence tube 3A is also moved to the position of the incidence electrode 18 and installed in the return yoke 5A. The suction tube 26 formed in the return yoke 5B of the accelerator 4A is also attached to the return yoke 5B of the accelerator 4A on the extension of the ion incident tube 3A.

  The bending points 24A to 24P of the magnetic poles 7A to 7F and the high frequency accelerating electrodes 9C and 9D are disposed on the inner side of the accelerator 4 and formed around the incident electrode 18, and a beam around which the 10 MeV ion beam circulates It is disposed on the orbit 78. The respective tips of the magnetic poles 7A to 7F and the high frequency accelerating electrodes 9C and 9D are pointed and face the incident electrode 18. The magnetic poles 7A to 7F and the high frequency accelerating electrodes 9C and 9D are tapered from their respective bending points toward the tip, similarly to their shapes shown in FIG. The lengths of the magnetic poles 7A to 7F and the high frequency accelerating electrodes 9C and 9D from the respective bending points to the end face facing the inner surface of the respective annular coil 11B are the respective ones in the return yoke 5B used for the accelerator 4 of the first embodiment. It is longer than its length. The lengths of the high frequency accelerating electrodes 9A and 9B disposed on the inner surface side of the annular coil 11B with respect to the bending points of the magnetic poles 7A to 7D are the same as those of the high frequency accelerating electrodes 9A and 9B used in the accelerator 4. It is slightly longer than the length.

  For this reason, the orbit concentric area formed around the incident electrode 18 in the return yoke 5B used for the accelerator 4A is smaller than that in the accelerator 4. Conversely, the orbital eccentric area formed around the orbital concentric area is larger than that in the accelerator 4.

  The return yoke 5A of the accelerator 4A also has magnetic poles 7A to 7F and high-frequency acceleration electrodes 9A to 9D in the same shape as the return yoke 5B of the accelerator 4A. The accelerator 4A includes the massless septum 12 except for the positions of the magnetic poles 7A to 7F and the high frequency accelerating electrodes 9A to 9D, and the positions of the incident electrode 18, the ion incident tube 3A and the suction tube 26. And the same configuration as the accelerator 4.

  Also in the particle beam irradiation apparatus 1A of the present embodiment, each step of steps S1 to S6, S23, S24, S7 to S14, S7 and S15 to S21 performed in the particle beam irradiation apparatus 1 is performed, and on the treatment table 55 The affected part of the patient 56 is irradiated with the ion beam.

  The present embodiment can obtain each effect produced in the first embodiment.

  The particle beam irradiation apparatus according to the third embodiment which is another preferred embodiment of the present invention will be described below with reference to FIG.

  The particle beam irradiation apparatus 1B of the present embodiment is different from the particle beam irradiation apparatus 1 of the first embodiment in the beam transport system and the rotating device of the accelerator 4. The accelerator 4, the irradiation device 7 and the control system 65 of the particle beam irradiation device 1 B are the same as those of the particle beam irradiation device 1.

  In Examples 1 and 2, the accelerators 4 and 4A are disposed horizontally, and the lower surface of the return yoke 5B of the vacuum vessel 27 is installed on the floor of the building. The particle beam irradiation apparatus 1B of the present embodiment has a rotary frame rotatably installed on the floor surface, and an accelerator 4 disposed vertically is attached to the rotary frame. This rotating frame has the same structure as the rotating frame described in Japanese Patent No. 3472657, and is supported by rotating rollers provided on a supporting device installed on the floor of a building. This supporting device is the same as the supporting device having a plurality of rollers for supporting a rotating gantry provided in a conventional particle beam irradiation device having a synchrotron (see JP-A-2006-239403). At least one of the rollers provided on the support device is rotated by a rotating device (e.g. a motor). The rotation of the roller causes the rotary frame to rotate, with which the accelerator 4 rotates about the central axis C of the vacuum vessel 27. The intermediate surface 77 formed in the vacuum vessel 27 is also perpendicular to the floor surface because the accelerator 4 is arranged vertically.

  The treatment room is surrounded by a radiation shielding wall (not shown), which has the same structure as the radiation surrounding described in Japanese Patent No. 3472657. A part of the radiation shielding wall is a side wall and is disposed between the accelerator 4 attached to the rotary frame and the treatment room. A treatment table 55 on which the patient 56 to be treated rests is placed in the treatment room.

  The beam path 48 of the beam transport system 13 B connected to the beam emission path 20 formed in the septum electromagnet 19 provided in the vacuum vessel 27 extends in the radial direction outside the vacuum vessel 27 and eventually becomes horizontal. It is curved and extends just above the treatment room along a radiation shielding wall that forms the ceiling of the treatment room. Beam path 48 is bent towards the treatment room directly above the treatment room. Deflection electromagnets 95, 96 are arranged at the bends of the beam path 48, which are provided with a plurality of quadrupole electromagnets 97. At the tip of the beam path 48, the irradiator 7 is attached. Similar to the particle beam irradiation apparatus 1 of the first embodiment, two scanning electromagnets 51 and 52, a beam position monitor 53, and a dose monitor 54 are attached to the irradiation apparatus 7.

  When the affected area of the patient 56 lying on the treatment table 55 in the treatment room is irradiated with the ion beam to treat the affected area, steps S1 to S1 performed in Example 1 are performed also in the proton beam treatment apparatus 1B. Steps S6, S23, S24, S7 to S14, S7 and S15 to S21 are performed. In particular, in the process of step S11 in the case of using the proton beam treatment apparatus 1B, the rotary frame is rotated to rotate the accelerator 4. At this time, the beam transport system 13B and the irradiation device 7 revolve around the rotation center (central axis C) of the accelerator 4. The beam axis of the irradiation device 7 is aligned with the irradiation direction of the ion beam to the affected area by the rotation of the irradiation device 7 as described above. At this time, the affected area of the patient 56 on the treatment table 55 is located on the extension of the center of rotation of the accelerator 4.

  By performing each process of steps S11 to S14, S7, and S15 to S21, irradiation of the ion beam to the affected area is performed, and the affected area is treated.

  The present embodiment can obtain each effect produced in the first embodiment. Furthermore, in the present embodiment, since the accelerator 4 is vertically disposed and rotated by the rotation frame, the size is smaller than that of the particle beam irradiation apparatus 1 of the first embodiment.

  The particle beam irradiation apparatus of Example 4 which is another preferable embodiment of the present invention will be described below with reference to FIGS. 29 and 30. FIG.

  The particle beam irradiation apparatus 1C of this embodiment has a configuration in which the ion beam generator 2 in the particle beam irradiation apparatus 1 is replaced by an ion beam generator 2A. Further, the ion beam generator 2A has a configuration in which the accelerator 4 in the ion beam generator 2 is replaced with an accelerator 4B. The accelerator 4 B has a configuration in which the massless septum 12, the moving device 17 and the power source 40 are eliminated in the accelerator 4 and an energy absorber 62 and a moving device 60 are added. The control system 65A used in the particle beam irradiation apparatus 1C has a configuration in which the accelerator / transport system controller 69 of the control system 65 is replaced with an accelerator / transport system controller 69A. The accelerator / transport system controller 69 A has a configuration in which the massless septum controller 86 in the accelerator / transport system controller 69 is replaced with an energy absorber controller 93. The energy absorber control device 93 is connected to the CPU 67, the memory 107, and the irradiation position control device 89, respectively. The other configuration of the accelerator / transport system controller 69 A is the same as that of the accelerator / transport system controller 69. The other configuration of the particle beam irradiation apparatus 1C is the same as that of the particle beam irradiation apparatus 1. Although not shown in FIGS. 29 and 30, the beam current measuring device 98 including the beam current measuring unit 15, the operation member 16A, the moving device 17 and the position detector 39 used in the particle beam irradiation device 1 is The particle beam irradiation apparatus 1C is also used. The beam current measuring device 98 is attached to the vacuum vessel 27 in the same manner as the particle beam irradiation device 1. The beam current measurement unit 15 and the operation member 16A are disposed on the intermediate surface 77 in the recess 29A.

  An energy absorber 62 is disposed in the vacuum vessel 27 between the magnetic pole 7A of the return yoke 5A and the return yoke 5B between the magnetic poles 7A of the return yoke 5A facing the magnetic pole 7A of the return yoke 5A. It is attached to the department. The energy absorber 62 is a thin plate of aluminum and is disposed perpendicular to the beam orbit 78. The energy absorber 62 may be made of a metallic or nonmetallic material which is a nonmagnetic material such as tungsten, copper and titanium instead of aluminum. The width in the direction perpendicular to the intermediate surface 77 of the energy absorber 62 is smaller than the gap between the magnetic pole 7A of the return yoke 5A and the magnetic pole 7A of the return yoke 5B.

  An operating member 63 attached to the energy absorber 62 penetrates the vacuum vessel 27 and extends to the outside of the vacuum vessel 27. The operating member 63 is also a support member for the energy absorber 62, and is connected to the piston of the moving device 60 having a piston and a cylinder outside the vacuum vessel 27. The operation member 63 is disposed between the above-described opposing magnetic poles 29A and between the annular coil 11A and the annular coil 11B, for example, through the cylindrical portion 75B of the return yoke 5B so as to be slidable in the cylindrical portion 75B. It is attached. A position detector 61 for detecting the position of the energy absorber 62 in the vacuum vessel 27 is attached to the moving device 60 (see FIG. 29). The moving device 60 may be a motor. When a motor is used as the moving device 60, an encoder is used as the position detector 38, and this encoder is connected to the rotation shaft of the motor. The energy absorber 62, the operation member 63, the moving device 60 and the position detector 61 constitute a beam extraction adjusting device which is a kind of beam separating device.

  Also in the particle beam irradiation apparatus 1C, each step excluding the steps S8 and S9 among the steps S1 to S6, S23, S24 and S7 to S10 described in the first embodiment is performed. Furthermore, between steps S7 and S10, the process of step S22 (see FIG. 32) described later is performed instead of steps S8 and S9. The process of step S22 will be described in detail later.

  When the affected area of the patient 56 on the treatment table 55 is irradiated with the ion beam to treat the affected area, steps S11, S12, S22, S7 and S15 to S21 shown in FIG. 32 are performed. Each process other than step S22 is implemented similarly to the first embodiment. Here, the process of step S22 will be described.

  The energy absorber is positioned (step S22). In order to carry out the process of step S22, the energy absorber control device 93 controls the moving device 60 based on the control command information from the CPU 67, and moves the operation member 63 by the moving device 60 to thereby form the energy absorber 62. Are moved toward the central axis C of the vacuum vessel 27 at the intermediate surface 77. Such movement of the energy absorber 62 allows the energy absorber 62 to cross each of the beam orbits 78 at which each ion beam of at least 70 MeV to 250 MeV orbits.

  The energy absorber control unit 93 determines the layer based on the energy information of the ion beam irradiated to the layer set in step S12 and the attenuation degree of the energy by the energy absorber 62, which are input from the irradiation position control unit 89. The position of a beam orbit 78 around which an ion beam of energy slightly higher than the energy of the ion beam to be irradiated is measured by the position detection device 39 and associated with the energy stored in the memory 107 It specifies based on the positional information on the orbit 78. The energy absorber controller 93 moves the energy absorber 62 to the specified position of the beam orbit 78 by controlling the identified moving device 60, and positions the energy absorber 62 on the beam orbit 78.

  The position of the energy absorber 62 in the radial direction of the intermediate surface 77 (the position in the vacuum chamber 27 in the radial direction) is measured by the position detector 61. The position information of the energy absorber 62 measured by the position detector 61 is input to the energy absorber control device 93. The energy absorber control unit 93 determines whether the measured position information of the energy absorber 62 matches the specified position of the beam orbit 78, and if not, the energy absorber The controller 93 controls the moving device 60 to move the energy absorber 62 to the position of its beam orbit. When the measured position information of the energy absorber 62 matches the position of the corresponding beam orbit, the energy absorber control device 93 stops the driving of the moving device 60.

  When the energy absorber 62 is positioned at the position of the beam orbit 78 specified above by the control of the moving device 60 by the energy absorber controller 93, ions are incident on the beam orbiting region 76 in step S16. Thereafter, the ion beam orbiting the beam orbit 78 at the specified position attenuates the energy as it passes through the energy absorber 62. As a result, the ion beam whose energy has been attenuated is substantially located outside with respect to the equilibrium orbit. Then, while moving to a recess 29 D having a beam exit path 20, the beam undergoes betatron oscillation and moves toward the entrance of the beam exit path 20. As a result, the ion beam having passed through the energy absorber 62 is emitted from the accelerator 4 B to the beam path 48 of the beam transport system 13 through the beam emission path 20.

  According to the treatment plan data, if the ion beam irradiated to the layer having the affected area is 200 MeV, it is necessary to emit an ion beam of 200 MeV to the beam path 48 from the accelerator 4B. It is necessary to set the energy of the ion beam that has passed through the energy absorber 62 to 200 MeV, and in this case, it is necessary to transmit the 205 MeV ion beam through the energy absorber 62 in consideration of the energy attenuation by the energy absorber 62. There is. In this case, the energy absorber 62 is positioned in the beam orbit where the 205 MeV ion beam orbits.

  When the determination of step S20 is "No", each process of steps S11, S12, S22, S7 and S15 to S20 is repeatedly performed until the determination of step S20 becomes "Yes". In this repetition, in step S22, the positioning of the energy absorber 62 as described above is performed.

  Among the effects obtained in the first embodiment, the present embodiment can obtain the remaining effects excluding the effect generated in the massless septum 12. In this embodiment, since the massless septum 12 having a complicated structure and the power source 40 are not required, the structure of the particle beam irradiation apparatus 1C is simplified.

  Since the moving device 17A for moving the energy absorber 62 in the radial direction of the annular coil is provided, a beam orbit where the ion beam having energy to be irradiated to the set layer of the affected part of the energy absorber 62 circulates. Adjustments of positioning to 78 can be made. Therefore, the positioning of the energy absorber 62 on the corresponding beam orbit 78 can be performed with high accuracy.

  The particle beam irradiation apparatus of the fifth embodiment which is another preferable embodiment of the present invention will be described below with reference to FIGS. 33 and 34. FIG.

  The particle beam irradiation apparatus 1D of the present embodiment has a configuration in which the accelerator 4 in the particle beam irradiation apparatus 1 is replaced with an accelerator 4C. The accelerator 4C has a configuration in which an energy absorber 62, an operation member 63 and a moving device 60 are added to the accelerator 4. The other configuration of the particle beam irradiation apparatus 1C is the same as that of the particle beam irradiation apparatus 1. The accelerator / transport system controller 69 used in the present embodiment includes an energy absorber controller 93 in addition to the massless septum controller 86. The thickness of the energy absorber 62 used in the present embodiment can be thinner than the thickness of the energy absorber 62 used in the fourth embodiment because the massless septum 12 is used.

  In particle beam irradiation apparatus 1D, each process of steps S1 to S6, S23, S24 and S7 to S10 described in the first embodiment is performed. Furthermore, in the case where the affected area of the patient 56 on the treatment table 55 is irradiated with the ion beam using the particle beam irradiation apparatus 1D to treat the affected area, steps S11, S12, S22, S13 and S14 shown in FIG. , S7 and S15 to S21 are performed. The process of step S22 is the same as the process performed in the fourth embodiment.

  Since the present embodiment is different from the first and fourth embodiments in the extraction of the ion beam in step S16 from the fact that the massless septum 12 and the energy absorber 62 are used, step S16 will be described in detail.

  An energy absorber 62 is disposed in front of the massless septum 12 in the circulation direction of the ion beam. For this reason, after the energy of the ion beam of a certain energy is attenuated by the energy absorber 62, the ion beam with the attenuated energy is kicked out by the massless septum 12. The ion beam whose energy is attenuated by the energy absorber 62 moves inward from the beam orbit which the ion beam had been orbiting before the energy was attenuated. Since the amount of movement of the ion beam is known in advance, in the positioning of the electrode in the massless septum 12 in step S13, the ion beam orbit before the energy attenuation is taken into consideration, in consideration of the amount of movement. The moving device 17 positions the pair of opposing magnetic poles 32A and 32B present at the inner side at the position of the ion beam transmitted through the energy absorber 62 as described above.

  For this reason, since the energy absorber 62 is disposed in the beam circulation orbit along which the ion beam generated after the ions are incident on the beam circulation region 76 in step S16, the ion beam that has passed through the energy absorber 62 The energy is attenuated to the energy of the ion beam irradiated to a certain layer of the affected area. The ion beam which has passed through the energy absorber 62 is further kicked out by the pair of excited magnetic poles 32A and 32B of the massless septum 12 which are positioned in advance. The kicked ion beam is incident on the beam emitting path 20 and emitted to the beam path 48 of the beam transport system 13.

  The present embodiment can obtain the effects produced in the first and fourth embodiments. In the present embodiment, since the massless septum 12 is used in combination, the thickness of the energy absorber 62 can be thinner than the thickness of the energy absorber 62 used in the fourth embodiment. Therefore, the scattering of the ion beam by the energy absorber 62 is reduced, and the ion beam emitted from the accelerator 4C to the beam transport system 13 is increased accordingly. The utilization efficiency of the ion beam utilized to treat patient 56 is increased.

  A particle beam irradiation apparatus according to a sixth embodiment which is another preferred embodiment of the present invention will be described below with reference to FIGS. 36, 37 and 38.

  The particle beam irradiation apparatus 1E of the present embodiment has a configuration in which the beam current measurement apparatus 98 in the particle beam irradiation apparatus 1 of the first embodiment is replaced by a beam current measurement apparatus 98A. The other configuration of the particle beam irradiation apparatus 1E is the same as that of the particle beam irradiation apparatus 1.

  The beam current measuring device 98A has a monitor case 101, a plurality of monitor electrodes 103A, and a plurality of monitor electrodes 103B, as shown in FIGS. The monitor housing 101 includes housing portions 102A and 102B and a connecting portion 102C, which are disposed in parallel to each other to face each other. The monitor electrodes 103A are arranged in a row with a predetermined interval, and attached to one surface of the housing 102A facing the housing 102B via a plurality of (for example, four) insulators 104. The respective monitor electrodes 103B are arranged in a line with a predetermined interval, and attached to one surface of the housing 102B facing the housing 102A via a plurality of (for example, four) insulators 104. The respective ends of the housing portions 102A and 102B are coupled by the coupling portion 102C. Each monitor electrode 103A is disposed to be opposed to each monitor electrode 103B one by one.

  An electrode lead wire 106 is connected to each monitor electrode 103A, and another electrode lead wire 106 is connected to each monitor electrode 103B. The electrode lead wires 106 connected to the monitor electrodes 103A are bundled and covered with an electrode lead cover 105A in order to prevent damage due to degassing and discharge in vacuum in the vacuum vessel 27. The electrode lead cover 105A is attached to this surface along the surface of the housing portion 102A. The electrode lead wires 106 connected to the monitor electrodes 103B are also bundled and covered with the electrode lead cover 105B in order to prevent damage due to degassing and discharge in vacuum in the vacuum vessel 27. The electrode lead cover 105B is attached to this surface along the surface of the housing portion 102B. The electrode lead wire 106 connected to each monitor electrode 103A and the electrode lead wire 106 connected to each monitor electrode 103B are bundled at the position of the connecting portion 102C and covered with an electrode lead cover (not shown) , And is taken out of the vacuum vessel 27 through the cylindrical portion 75B of the return yoke 5B. These electrode lead wires 106 are connected to a beam current measurement unit controller 84.

  The beam current measuring device 98A is disposed between the magnetic poles 32A of the massless septum 12 and the magnetic poles 32B opposite thereto as shown in FIGS. 38 and 39, and is attached to the massless septum 12. Also in the present embodiment, the massless septum 12 is disposed in the recess 29A formed in each of the facing return yokes 5A and 5B. For this reason, the beam current measuring devices 98A are also arranged in their recesses 29A. A beam passage 35, which is a gap through which the circulating ion beam passes, is formed between each of the monitor electrodes 103A and each of the monitor electrodes 103B. The beam passage 35 includes a part of the intermediate surface 77. The monitor electrodes 103A and the monitor electrodes 103B face each other with the intermediate surface 77 interposed therebetween. The length of the monitor housing 101 is longer than the length of the massless septum 12, and the monitor housing 101 includes, for example, a beam orbit of ion beam of 35 MeV to a beam orbit of ion beam of 250 MeV 78. A plurality of monitor electrodes 103A and a plurality of monitor electrodes 103B are provided so that the beam current can be measured.

  In the particle beam irradiation apparatus 1E of the present embodiment, each step of steps S1 to S6, S23, S24, S7 to S14, S7 and S15 to S21 performed by the particle beam irradiation apparatus 1 is performed, and The affected part of the patient 56 is irradiated with the ion beam. Among these steps, step S6 (measurement of ion beam) performed in the present embodiment will be specifically described. In the present embodiment, step S6 is performed using the beam current measuring device 98A. After the steps S1 to S5 are performed, the position of the massless septum 12 is adjusted using the moving device 17, and each of the monitor electrodes 103A and 103B of the beam current measuring device 98A is set along the alternate long and short dash line X. Adjust to the position of. The respective ion beams orbiting each beam orbit 78 pass through the beam path 35. The voltage generated between the ion beams as they pass between the facing monitor electrodes 103A and 103B is measured. The measured voltage information corresponding to the beam current is converted into a beam current, and the respective energy information corresponding to the beam current is the position of these monitor electrodes on the alternate long and short dash line X in the radial direction of the annular coil. The information is stored in the memory 107 in association with the position information of the beam orbit 78 in the radial direction.

  In step S13, the massless septum control device 86 determines the information on the energy of the ion beam irradiated to the set layer and the position of the beam orbit 78 associated with the energy (voltage information) stored in the memory 107. Based on the information, a pair of magnetic poles 32A, 32B to be positioned and excited in the corresponding beam orbit 78 is identified. Further, similarly to step S13 in the first embodiment, the movement amount of the massless septum 12 is obtained. The massless septum control device 86 controls the moving device 17 based on the amount of movement to move the massless septum 12 toward the incident electrode 18, and the corresponding beam orbit 78 of the identified magnetic poles 32A and 32B. Positioning is made. Further, in step S14, the specified pair of magnetic poles 32A and 32B is excited.

  The present embodiment can obtain each effect produced in the first embodiment.

  The beam current measuring device 98 used in the first embodiment detects the beam current by causing the beam current measuring unit 15 to collide with the circulating ion beam. Therefore, in order to destroy and measure the circulating ion beam, a moving device 17A for moving the beam current measurement unit 15 is required. In order to measure the beam current of the ion beam orbiting the beam orbit 78 located at the outermost periphery, it is necessary to extract the beam current measurement unit 15 to the vicinity of the inner surface of the annular coils 11A and 11B, and the operation member 16A must be long. There is a possibility. Therefore, there is a concern that the beam current measuring device 98 should be enlarged.

  The beam current measuring apparatus 98A used in this embodiment measures the above-mentioned voltage corresponding to the beam current of the ion beam using the opposing monitor electrodes 103A and 103B, without destroying the circulating ion beam. The voltage can be measured and the beam current corresponding to the voltage can be determined. In addition, since the moving device 17 of the massless septum 12 can be used to finely adjust the positions of the monitor electrodes 103A and 103B, the beam current measuring device 98A can be smaller than the beam current measuring device 98. it can.

  The beam current measuring device 98A disposed in the massless septum 12 may be fixed to the cylindrical body 75B of the return yoke 5B using a rod-like support member 108 as in the seventh embodiment described later. In this case, the support member 108 attached to the beam current measuring device 98A reaches the outside of the massless septum 12 through the through hole 31D formed in the connection portion 31 of the massless septum 12.

  The particle beam irradiation apparatus of the seventh embodiment which is another preferred embodiment of the present invention will be described below with reference to FIGS. 42 and 43. FIG.

  The particle beam irradiation apparatus 1F of the present embodiment has a configuration in which the beam current measurement apparatus 98 in the particle beam irradiation apparatus 1C of the fourth embodiment is replaced with the beam current measurement apparatus 98A described above. The other configuration of the particle beam irradiation apparatus 1F is the same as that of the particle beam irradiation apparatus 1C. In the particle beam irradiation apparatus 1F, the beam current measuring apparatus 98A is disposed in the recess 29A formed in each of the return yokes 5A, 5B along the alternate long and short dash line X perpendicular to the central axis C through the central axis C. The support member 108 is attached to the cylindrical portion 75B of the return yoke 5B. A portion of the intermediate surface 77 in which the beam orbiting trajectory 78 is formed is present in the beam passage 35 formed in the beam current measuring device 98A. The monitor electrodes 103A and the monitor electrodes 103B face each other with the intermediate surface 77 interposed therebetween.

  In the present embodiment, similarly to the fourth embodiment, the respective steps excluding the respective steps of the steps S8 and S9 out of the respective steps of the steps S1 to S6, S23, S24 and S7 to S10 described in the first embodiment are performed. Furthermore, each process of steps S11, S12, S22, S7 and S15 to S21 shown in FIG. 35 is performed.

  Also in the present embodiment, in step S6, as in the sixth embodiment, when the ion beam is circulating, the voltage between the monitor electrode 103A and the monitor electrode 103B facing each other is detected using the beam current measuring device 98A. taking measurement. Further, in step S22, based on the information on the energy of the ion beam irradiated to the set layer and the attenuation degree of the energy by the energy absorber 62, the energy slightly higher than the energy of the ion beam to be irradiated to the layer Based on the position information associated with the voltage information, which is the beam current information stored in the memory 107, the position of the beam orbit 78 around which the ion beam revolves is specified. The energy absorber controller 93 moves the energy absorber 62 to the specified position of the beam orbit 78 by controlling the moving device 60.

  The present embodiment can obtain each effect produced in the fourth embodiment. Furthermore, the present embodiment can also obtain the effects produced by the beam current measuring device 98A in the sixth embodiment.

  A particle beam irradiation apparatus according to an eighth embodiment which is another preferred embodiment of the present invention will be described below with reference to FIGS. 44, 45 and 46.

  The particle beam irradiation apparatus described in the first to seventh embodiments of the particle beam irradiation apparatus 1 and the like has a vacuum vessel 27 in which each accelerator is configured using iron cores 14A and 14B. However, in the particle beam irradiation apparatus 1G of the present embodiment, the accelerator 4D includes the iron cores 14A and 14B, and further includes the vacuum vessel 27A disposed between the iron core 14A and the iron core 14B. The vacuum vessel 27A is made of a nonmagnetic material (for example, stainless steel). The iron core 14A is disposed above the vacuum vessel 27A, and the iron core 14B is disposed below the vacuum vessel 27A. The massless septum 12 and the beam current measuring unit 15 of the beam current measuring device 98 are disposed in the vacuum chamber 27A. An intermediate surface 77 on which the beam orbit 78 is formed is formed in the vacuum vessel 27A perpendicular to the central axis C of the vacuum vessel 27 and the annular coils 11A and 11B. The ion incident tube 3A penetrates the base portion 74A of the return yoke 5A included in the iron core 14A and reaches the inside of the vacuum vessel 27A. An ion injection port formed at the tip of the ion injection tube 3A opens into the vacuum vessel 27A. A suction tube 26 disposed on an extension of the central axis of the ion incidence tube 3A is attached to the base portion 74B through the base portion 74B of the return yoke 5B. The suction pipe 26 is connected to the vacuum vessel 27A and opens into the vacuum vessel 27A. The incidence electrode 18 is attached to the tip of the ion implantation tube 3A.

  The other configuration of the particle beam irradiation apparatus 1G including the iron cores 14A and 14B is the same as the particle beam irradiation apparatus 1.

  The operation member 16 attached to the massless septum 12 and the operation member 16A attached to the beam current measurement unit 15 penetrate the vacuum vessel 27A and the cylindrical portion 75B of the return yoke 5B to reach the outside of the return yoke 5B. The operating members 16 and 16A are connected to the moving devices 17 and 17A outside the return yoke 5B. The septum electromagnet 19 is attached to the vacuum vessel 27A and the cylindrical portion 75B. The beam exit path 20 formed in the septum electromagnet 19 is in communication with the beam path 48 of the beam transport system 13. The inlet of the beam emission path 20 is located in the vacuum vessel 27A.

  On the intermediate surface 77 in the vacuum vessel 27A, the above-described orbit concentric area and an orbit eccentric area surrounding the orbit concentric area are formed. The orbital concentric area and the orbital concentric area surround the incident electrode 18. The beam orbits 78 formed in the orbit concentric region are integrated on the entrance side of the beam outgoing path 20 as in the embodiment. Also in this embodiment, the positions of the incidence electrode 18 and the ion implantation port are shifted from the center axis C of the annular coil, that is, the center of gravity of the annular coil located on the central axis C to the entrance of the beam emission path 20 , Is located at a position different from the center of gravity of the annular coil in the radial direction of the accelerator 4D. As in the first embodiment, each of the magnetic poles 7A to 7F formed on the iron cores 14A and 14B is disposed so as to surround the position of the ion implantation port and radially extends from the position of the ion implantation port. Recesses 29A to 29F formed in iron cores 14A and 14B are also disposed surrounding the periphery of the position of the ion injection port, as in the first embodiment, and extend radially from the position of the ion injection port.

  In the present embodiment, as in the first embodiment, the magnetic field distribution shown in FIG. 10 is formed on the intermediate surface 77, and steps S1 to S6, S23, S24, S7 to S14, S7 and S15 to S21 are performed. The ion beam is irradiated to the affected area of the patient 56 on the treatment table 55.

  The present embodiment can obtain each effect produced in the first embodiment. In this embodiment, since the vacuum container 27A is separately provided, as in the embodiment 1, the opposing surfaces of the cylindrical portion 75A of the return yoke 5A and the cylindrical portion 75B of the return yoke 5B facing each other are sealed. There is no need. However, in the present embodiment, since the vacuum container 27A is disposed between the iron core 14A and the iron core 14B, the accelerator 4D used in the present embodiment is larger than the accelerator 4 used in the first embodiment.

  As shown in FIG. 47, even if the massless septum 12 is disposed outside the vacuum vessel 27A and this vacuum vessel 27A is disposed between each magnetic pole 32A of the massless septum 12 and each magnetic pole 32B opposed thereto. Good. In this case, the beam current measurement unit 15 is disposed on the intermediate surface 77 in the vacuum vessel 27A. The massless septum 12 arranged in this manner can also kick an ion beam orbiting the beam orbit 78 formed on the intermediate surface 77 in the vacuum vessel 27 A, and this ion beam can be used as the beam exit path 20. Can be emitted to the beam transport system 13.

  The particle beam irradiation apparatus of Example 9, which is another preferable embodiment of the present invention, will be described below with reference to FIG.

  In the particle beam irradiation apparatus 1F of this embodiment, as in the particle beam irradiation apparatus 1E, the vacuum vessel 27A is disposed between the iron core 14A and the iron core 14B. The particle beam irradiation apparatus 1F includes iron cores 14A and 14B, a vacuum vessel 27A, and an accelerator 4E having a beam current measurement unit 15 and an energy absorber 62 disposed in the vacuum vessel 27A. The operating member 16A attached to the beam current measurement unit 15 and the operating member 62 attached to the energy absorber 62 penetrate the cylindrical portion 75B of the vacuum vessel 27A and the return yoke 5B to reach the outside of the return yoke 5B.

  In the present embodiment, as in the fourth embodiment, the magnetic field distribution shown in FIG. 10 is formed on the intermediate surface 77, and among the steps S1 to S6, S23, S24 and S7 to S10 described in the first embodiment, Each process except each process of S8 and S9 is implemented. Further, each step of steps S11, S12, S22, S7 and S15 to S21 shown in FIG. 32 is performed. Also in the present embodiment, the ion beam emitted from the vacuum container 27A to the beam transport system 13 is applied to the affected area of the patient 56 on the treatment table 55.

  The present embodiment can obtain each effect produced in the fourth embodiment. However, in the present embodiment, since the vacuum vessel 27A is disposed between the iron core 14A and the iron core 14B, the accelerator 4D used in the present embodiment is larger than the accelerator 4B used in the fourth embodiment.

In the present invention, in place of the ion source 3 for generating protons, an ion source for generating carbon ions (C ^{4 +} ) is used, and the carbon ions (C ^{4 +} ) are charge converted by a charge converter to The carbon ion beam (C ^{6 +} ion beam) may be generated by converting it into C ^{6 +} ) in the accelerator, and the generated carbon ion beam may be emitted from the accelerator and guided to the irradiation device 7 through the beam transport system . In this case, a carbon ion beam is irradiated to the affected area of the patient 56 on the treatment table 55 instead of the proton ion beam. Furthermore, a helium ion beam may be emitted from the accelerator to the beam transport system using an ion source that generates helium ions as the ion source 3.

  In the present application, the positional relationship between elements which do not exist in a plane perpendicular to the central axis C of the annular coils 11A and 11B projects these elements on the intermediate plane 77 in the central axis C direction. It means the positional relationship between those elements in. The positional relationship between such elements is, for example, the ion injection port (ion injection port) formed at the tip of the ion injection tube 3A described in the eighth and ninth embodiments or the injection electrode 18 or ion injection portion and the magnetic pole 7A to 7F, high frequency accelerating electrodes 9A to 9D, positional relationship with the beam emitting path 20 and the recesses 29A to 29F, magnetic poles 7A to 7F, high frequency accelerating electrodes 9A to 9D, beam emitting path 20 and the recesses 29A to 29F And the positional relationship between the ion implantation port and the inlet of the beam emission path 20.

  1, 1A, 1B, 1C, 1D, 1E, 1F: particle beam irradiation device, 2, 2A, 2B: ion beam generator, 3: ion source, 3A: ion injection tube, 4, 4A, 4B, 4C, 4D , 4E: Accelerator, 6: Rotational gantry, 7: Irradiation device, 7A to 7F, 32A, 32B: Magnetic pole, 8A to 8F: Trim coil, 9A to 9D: High frequency accelerating electrode, 11A, 11B: Annular coil, 12: Mass Les-septum 13, 13 B: Beam transport system, 14 A, 14 B: iron core, 15: beam current measurement unit, 17, 17 A, 60: moving device, 18: incidence electrode, 19: septum electromagnet, 20, 48: beam path 24A-24P: bending point 27, 27A: vacuum vessel, 29A-29F: recess, 30, 30A, 30B: iron core member, 31A, 31B: iron core portion, 31C: connecting portion, 33A, 3B: coil, 35: beam passage, 36: high frequency power supply, 37, 40, 57, 80, 82: power supply, 51, 52: scanning electromagnet, 53: beam position monitor, 54: dose monitor, 62: energy absorber, DESCRIPTION OF SYMBOLS 65 ... Control system, 66 ... Central control apparatus, 69, 69A, 69B ... Accelerator-transport system control apparatus 70 ... Scanning control apparatus, 76 ... Beam circulation area | region 77 ... Intermediate surface, 83 ... Electrode control apparatus for incidence 84, ... Beam current measuring unit controller, 85 ... electromagnet controller, 86 ... massless septum controller, 88 ... rotation controller, 89 ... irradiation position controller, 91 ... dose determination device, 92 ... layer determination device, 93 ... energy Absorber control device 94 Coil current control device 98, 98A Beam current measuring device 99 High frequency voltage control device 101 Monitor housing 103 Monitor The pole.

Claims (4)

  An accelerator for generating a charged particle beam;
  A beam transport system which is a transport path of the charged particle beam;
  An irradiation device for forming an irradiation field by the charged particle beam transported via the beam transport system;
  Particle therapy apparatus having the
  The accelerator is
  An iron core, a coil and an accelerating electrode for controlling the acceleration and orbit of the charged particle beam;
  A substantially disk-shaped beam circulation region is formed in the region surrounded by the iron core for circulating and accelerating the charged particle beam,
  And an ion source provided at a position different from the center position of the beam circulation region so as to have an incident point of ions to the beam circulation region,
  A proximal end of a beam outgoing path, which is a path for taking out a charged particle beam after acceleration, is provided on the opposite side of the central position with respect to the incident point,
  The accelerator is configured to form a plurality of annular beam orbits that are offset from one another for each energy of the charged particle beam
  Particle therapy apparatus characterized in that.   The particle beam therapy system according to claim 1, wherein
  The center of the orbit of the charged particle beam of the first energy is a first center, and the center of the orbit of the charged particle beam of a second energy larger than the first energy is a second center.
  The second center is closer to the center of the coil than the first center
  Particle therapy apparatus characterized in that.   An accelerator for generating a charged particle beam;
  A beam transport system which is a transport path of the charged particle beam;
  An irradiation device for forming an irradiation field by the charged particle beam transported via the beam transport system;
  Particle therapy apparatus having the
  The accelerator is
  An iron core, a coil and an accelerating electrode for controlling the acceleration and orbit of the charged particle beam;
  A substantially disk-shaped beam circulation region is formed in the region surrounded by the iron core for circulating and accelerating the charged particle beam,
  And an ion source provided at a position different from the center position of the beam circulation region so as to have an incident point of ions to the beam circulation region,
  A proximal end of a beam outgoing path, which is a path for taking out a charged particle beam after acceleration, is provided on the opposite side of the central position with respect to the incident point,
  The orbit of the charged particle beam of the first energy is a first orbit, and the orbit of the second energy different from the first energy is a second orbit.
  The distance between the first circumferential orbit and the second circumferential orbit on the proximal side with respect to the incident point is the first circumferential orbit and the second circumferential orbit on the opposite side to the proximal end with respect to the incident point. Narrower than the distance between
  Particle therapy apparatus characterized in that.   The particle beam therapy system according to any one of claims 1 to 3, wherein
  A massless septum is provided on the opposite side of the proximal end of the beam emission path with respect to the incident point, the massless septum kicking from the orbit of the charged particle beam orbiting the beam orbiting region.
  Particle therapy apparatus characterized in that.

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