JP7500159B2 - PARTICLE BEAM THERAPY APPARATUS AND METHOD FOR OPERATION OF PARTICLE BEAM THERAPY APPARATUS - Patent application - Google Patents

Description

FIELD OF THE DISCLOSURE Embodiments of the present invention relate to particle therapy devices and methods of operating particle therapy devices .

Conventionally, particle beam therapy devices are equipped with an energy modulation filter to expand the range in which the Bragg peak of the particle beam occurs in the direction of beam propagation. In particular, in a method called scanning irradiation, this energy modulation filter widens the Bragg peak of the particle beam, thereby mitigating position errors or shortening the irradiation time.

U. Weber and G. Kraft, "Design and construction of a ripple filter for a smoothed depth dose distribution in conformal particle therapy," Phys. Med. Biol.44, 2765-75 (1999). T. P. Ringbak, Y. Simeonov and M. Witt et al., "Modulation power of porous materials and usage as ripple filter in particle therapy", Phys. Med. Biol.62, 2892-2909 (2017).

When the Bragg peak of a particle beam is broadened using a filter for energy modulation, there is a secondary property that the beam size also unintentionally widens due to multiple Coulomb scattering and nuclear reactions that occur within the filter, compared to a monoenergetic particle beam without a filter. This causes the particle beam to expand in the radial direction, which poses the problem of reduced dose concentration at the affected area. In addition, in order to suppress the effects of beam irradiation on healthy tissue and increase dose concentration at the affected area, it is desirable to make the beam size as small as possible.

The embodiment of the present invention has been made in consideration of these circumstances, and aims to provide a particle beam therapy technology that can broaden the Bragg peak of a particle beam while suppressing the radial broadening of the particle beam.

A particle beam therapy device according to an embodiment of the present invention includes a beam extraction unit that extracts a particle beam toward a patient, an irradiation port cover that covers the beam extraction unit, and an energy modulation unit that is provided in correspondence with a portion of the irradiation port cover that is closest to the patient and that widens the Bragg peak of the particle beam passing through the irradiation port cover. The irradiation port cover is U-shaped in cross section, and the energy modulation unit is located at the bottom of the irradiation port cover.

Embodiments of the present invention provide a particle beam therapy technique that can broaden the Bragg peak of a particle beam while suppressing the radial broadening of the particle beam.

1 is a conceptual diagram showing the overall configuration of a particle beam therapy system according to a first embodiment. FIG. FIG. FIG. 4 is a cross-sectional view showing the irradiation port with the opening portion opened. FIG. 13 is a cross-sectional view showing the irradiation port when the second energy modulation unit is replaced. FIG. 5 is a plan view showing an irradiation port corresponding to FIG. 4; FIG. 6 is a plan view showing an irradiation port corresponding to FIG. 5 . FIG. 4 is an enlarged perspective view showing a ridge filter as an energy modulation section. FIG. 4 is an enlarged side view showing a state in which a particle beam passes through a ridge bar. FIG. FIG. 4 is a perspective view showing the arrangement of two ridge filters. Graph showing the relationship between relative dose and depth. FIG. 4 is an explanatory diagram showing a slice plane set on an affected area. FIG. 4 is an explanatory diagram showing an irradiation spot that scans a slice surface. FIG. 4 is an enlarged side view showing each step of the ridge bar. 1 is a graph showing the relationship between each step and the Bragg peak. FIG. 13 is an explanatory diagram showing a Gaussian distribution when the first energy modulation unit is used alone. FIG. 13 is an explanatory diagram showing a Gaussian distribution when the second energy modulation unit is used alone. FIG. 13 is an explanatory diagram showing a Gaussian distribution when the first energy modulation unit and the second energy modulation unit are used in combination. FIG. 1 is a block diagram showing the system configuration of a particle beam therapy apparatus. 13 is a flowchart showing a replacement process of a second energy modulation unit. 13 is a flowchart showing a replacement process of a second energy modulation unit. 4 is a flowchart showing a particle beam therapy process. FIG. 11 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to a second embodiment. FIG. 11 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to a third embodiment. FIG. 13 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to a fourth embodiment. FIG. 13 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to a fifth embodiment. FIG. 13 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to a sixth embodiment. FIG. 23 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to a seventh embodiment. FIG. 23 is a cross-sectional view showing an irradiation port of a particle beam therapy apparatus according to an eighth embodiment.

First Embodiment
Hereinafter, the present embodiment will be described with reference to the accompanying drawings. First, a particle beam therapy system according to a first embodiment will be described with reference to Fig. 1 to Fig. 23. Reference numeral 1 in Fig. 1 denotes a particle beam therapy system. In this particle beam therapy system 1, a particle beam such as carbon ions is irradiated onto a lesion tissue (cancer) of a patient as a subject to perform treatment.

Radiation therapy technology using the particle beam therapy device 1 is also known as heavy particle beam cancer therapy technology. This technology uses carbon ions to pinpoint the cancer lesion (affected area), damaging the cancer lesion while minimizing damage to normal cells. Particle beams are defined as radiation heavier than electrons, and include proton beams and heavy particle beams. Of these, heavy particle beams are defined as those heavier than helium atoms.

Compared to conventional cancer treatments using X-rays, gamma rays, or proton beams, cancer treatments using heavy ion beams have a higher ability to kill cancer lesions, and have the characteristic that the radiation dose is low on the surface of the patient's body and peaks at the cancer lesion. This allows for fewer irradiations and fewer side effects, and shorter treatment periods.

Figure 1 is a plan view showing the overall configuration of the particle beam therapy device 1. Figure 2 is a cross-sectional view of the rotating gantry 5 as seen from the side. Note that the left side of the page in Figure 2 will be described as the front side (forward side) of the particle beam therapy device 1.

As shown in Figures 1 and 2, the particle beam therapy device 1 includes a beam generator 2 having an ion source that generates carbon ions, which are charged particles, a ring-shaped circular accelerator 3 that accelerates the carbon ions to form a particle beam B, a beam transport line 4 that transports the particle beam B, and a rotating gantry 5 in which a patient P to be irradiated with the particle beam is positioned.

First, carbon ions generated in the ion source are injected from the beam generator 2 into the circular accelerator 3. These carbon ions are accelerated to approximately 70% of the speed of light while orbiting the circular accelerator 3 approximately one million times, becoming a particle beam B. This particle beam B is then guided to the rotating gantry 5 via the beam transport line 4.

The circular accelerator 3 and the beam transport line 4 are equipped with a vacuum duct D (beam pipe) whose interior is evacuated. The particle beam B travels through the interior of this vacuum duct D. The vacuum ducts D of the circular accelerator 3 and the beam transport line 4 work together to form a transport path that guides the particle beam B to the rotating gantry 5. In other words, the vacuum duct D is a sealed continuous space with a sufficient degree of vacuum to allow the particle beam B to pass through.

The circular accelerator 3 includes a radio-frequency acceleration cavity 22 that accelerates carbon ions by controlling the frequency of the magnetic field and the accelerating electric field, and a bending electromagnet 23 that controls the direction of travel of the particle beam B into a circular shape.

The beam transport line 4 also includes a bending electromagnet 24 used to change the direction of travel of the particle beam B, and a control quadrupole electromagnet 25 that controls the convergence and divergence of the particle beam B.

Each of the electromagnets 23-25 is arranged to surround the outer periphery of the vacuum duct D. Furthermore, multiple electromagnets 23-25 are lined up along the direction in which the vacuum duct D extends. Note that other devices or electromagnets may be provided in the circular accelerator 3 or the beam transport line 4.

As shown in FIG. 2, the rotating gantry 5 is a large cylindrical device. The rotating gantry 5 is installed so that the rotation axis J of the cylinder faces horizontally. The rotating gantry 5 can rotate around the rotation axis J.

In addition, support rollers 7 that support the rotating gantry 5 in a rotatable state and a drive motor 8 that serves as a rotation drive unit that rotates the rotating gantry 5 around the rotation axis J are provided below the rotating gantry 5.

The rotating gantry 5 is supported by the support rollers 7 via end rings 9 fixed to its outer periphery. The rotational driving force of the drive motor 8 is applied to the rotating gantry 5 via the support rollers 7 and the end rings 9.

A vacuum duct D and a bending electromagnet 6 are attached to the rotating gantry 5, which are extended from the beam transport line 4. In the rotating gantry 5, the vacuum duct D is first guided from the outside of the rotating gantry 5 along its rotation axis J, and after once extending toward the cylindrical outer periphery of the rotating gantry 5, it again extends toward the inner periphery of the rotating gantry 5. The bending electromagnet 6 is used to change the direction of travel of the particle beam B along the vacuum duct D.

In addition, an irradiation port 10 is provided at the end of the vacuum duct D, which irradiates the particle beam B guided by the beam transport line 4 toward the patient P. This irradiation port 10 is fixed to the inner peripheral surface of the rotating gantry 5. The particle beam B is irradiated from the irradiation port 10 in a direction perpendicular to the rotation axis J.

In addition, a rotation mechanism is provided in the vacuum duct D in the portion along the rotation axis J of the rotating gantry 5, and this portion rotates together with the rotation of the rotating gantry 5.

As shown in Figures 3 and 11, a scanning electromagnet 11 is provided near the end of the vacuum duct D. This scanning electromagnet 11 has an X-deflection scanning magnet that deflects and scans the particle beam B in the X direction and a Y-deflection scanning magnet that deflects and scans the particle beam B in the Y direction. The scanning electromagnet 11 controls the particle beam B to scan the thin particle beam B by three-dimensionally matching it to the shape of the affected area of the patient P. In other words, the particle beam B irradiated from the irradiation port 10 can scan over a predetermined scanning range F in two directions (X direction and Y direction) perpendicular to the beam traveling direction.

As shown in FIG. 2, a treatment space 12 in which particle beam therapy is performed is provided inside the rotating gantry 5. The patient P is placed on a treatment table 13 provided in this treatment space 12. This treatment table 13 is movable with the patient P placed on it. By moving this treatment table 13, the patient P can be moved to the irradiation position of the particle beam B and aligned. Therefore, the particle beam B can be irradiated to the lesion tissue of the patient P with optimal accuracy.

In addition, by rotating the rotating gantry 5, the irradiation port 10 can be rotated around the patient P. For example, the irradiation port 10 can be rotated 180 degrees clockwise or counterclockwise when viewed from the front around the patient P (rotation axis J). Then, the particle beam B can be irradiated from any direction around the patient P. In other words, the rotating gantry 5 is a device that can change the irradiation direction of the particle beam B guided by the beam transport line 4 to the patient P. Therefore, the particle beam B can be accurately irradiated to the affected area from the optimal direction while reducing the burden on the patient P.

As the particle beam B passes through the body of the patient P, it loses kinetic energy and slows down, and encounters resistance that is roughly inversely proportional to the square of the velocity, causing it to suddenly stop when it has slowed to a certain speed. This stopping point of the particle beam B is called the Bragg peak, and high energy is released from it. By aligning this Bragg peak with the position of the diseased tissue (affected area) of the patient P, the particle beam therapy device 1 can destroy only the diseased tissue while minimizing damage to normal tissue.

As shown in FIG. 2, the treatment space 12 provided inside the rotating gantry 5 is formed to be integrated with the treatment room 15 connected to the building 14. The floor, walls, and ceiling of the treatment room 15 on the building 14 side are provided to be connected to the treatment space 12. The treatment table 13 is fixed to the floor of the treatment room 15 on the building 14 side. In other words, even if the rotating gantry 5 and irradiation port 10 are rotated, the position of the treatment table 13 does not change.

The patient P enters the treatment space 12 through the treatment room 15. When the irradiation port 10 is viewed from the treatment room 15, the surface facing the line of sight G1 of the patient P, i.e., the surface visible to the patient P, will be described as the front side of the irradiation port 10, and the opposite side will be described as the back side of the irradiation port 10.

An inner wall 16 is provided inside the rotating gantry 5. This inner wall 16 is disk-shaped, and its periphery is supported by a support portion 17 provided around the entire circumference of the inner circumferential surface of the rotating gantry 5. This inner wall 16 is supported by the support portion 17 so that it can rotate freely in the circumferential direction. This inner wall 16 divides the inside of the rotating gantry 5 into the treatment space 12 and the rest of the area.

A reverse rotation synchronous motor 18 is connected to the center of the inner wall portion 16 on the opposite side to the treatment space 12. This reverse rotation synchronous motor 18 is fixed to the inner peripheral surface of the rotating gantry 5. When the rotating gantry 5 is rotated by the driving force of the drive motor 8, the reverse rotation synchronous motor 18 rotates the inner wall portion 16 in the direction opposite to the rotation direction of the rotating gantry 5.

For example, when the rotating gantry 5 rotates clockwise when viewed from the front, the inner wall portion 16 rotates counterclockwise. At this time, the rotation speed of the rotating gantry 5 and the rotation speed of the inner wall portion 16 are made the same. In other words, even when the rotating gantry 5 rotates, the inner wall portion 16 appears to be stationary. Note that a decorative wall 19 is provided on the treatment space 12 side of the inner wall portion 16 to conceal the inner wall portion 16 so that it cannot be seen from the treatment space 12 side.

Inside the rotating gantry 5, there are a front track rail 20a provided at one end (front side), a rear track rail 20b provided at the other end (rear side), and multiple moving floors 21 that are stretched between these track rails 20a, 20b.

The movable floors 21 are rectangular plate-shaped members that are long in the front-to-rear direction. The floor, walls, and ceiling of the treatment space 12 are formed by these movable floors 21. The front track rail 20a is fixed to the floor, walls, and ceiling of the treatment room 15 on the building 14 side. Meanwhile, the rear track rail 20b is fixed to the inner wall portion 16. Even when the rotating gantry 5 and irradiation port 10 rotate, the front and rear track rails 20a, 20b remain stationary and do not rotate.

The movable floor 21, which is suspended between the track rails 20a and 20b, is aligned along the track rails 20a and 20b and is movable along the track rails 20a and 20b. When the irradiation port 10 rotates along with the rotation of the rotating gantry 5, the movable floor 21 moves in conjunction with the rotation of the irradiation port 10. No matter which position the irradiation port 10 is moved to, the movable floor 21 maintains the floor, walls, and ceiling of the treatment space 12.

In this way, the floor, walls, and ceiling of the treatment space 12 are formed by the decorative walls 19 and the movable floor 21, so the mechanical components that make up the rotating gantry 5 are invisible to the patient P in the treatment space 12. This improves the appearance of the interior of the treatment space 12. In addition, the patient P does not feel that he or she is inside a huge device, so the patient P does not feel psychologically oppressed.

Figures 3 to 5 are cross-sectional views of the irradiation port 10 in a rear view. Note that FIG. 3 illustrates a case where the irradiation port 10 is arranged above the patient P. Here, the irradiation port 10 rotates together with the rotation of the rotating gantry 5, so the irradiation port 10 may be arranged below the patient P. In that case, the configuration of the irradiation port 10 in FIG. 3 is inverted upside down. For convenience of explanation, the state where the irradiation port 10 is arranged above the patient P is taken as a fixed position, and the upper side of the paper of FIG. 3 to FIG. 5 is described as the upper side of the irradiation port 10. Also, FIG. 6 to FIG. 7 are cross-sectional views of the irradiation port 10 in a plan view. Note that the upper side of the paper of FIG. 6 to FIG. 7 is described as the front side (front side) of the irradiation port 10.

As shown in FIG. 3, a beam emission section 30 is provided inside the irradiation port 10. A particle beam B is emitted toward the affected area K of the patient P through this beam emission section 30. The position and orientation of the beam emission section 30 with respect to the patient P can be changed according to the rotation of the rotating gantry 5.

This beam emission section 30 is the downstream end of the vacuum duct D extending from the beam transport line 4, and is the section where the particle beam B guided along the vacuum duct D is emitted into the atmosphere. The opening at the downstream end of the vacuum duct D that forms this beam emission section 30 is blocked with a polyimide film, and the particle beam B can be emitted while maintaining a vacuum inside the vacuum duct D. In other words, the opening at the downstream end of the vacuum duct D is a thin-film vacuum window through which the particle beam B emerges.

The irradiation port 10 includes an irradiation port cover 31 and a torso cover 32. The irradiation port 10 further includes a beam emission section 30 covered by the irradiation port cover 31. The irradiation port cover 31 is a portion closest to the patient P and forming an approximately square shape in rear view. The torso cover 32 is a portion forming an approximately trapezoid shape in rear view. The irradiation port cover 31 and the torso cover 32 are formed of a non-metallic material such as synthetic resin (e.g., GFRP). The irradiation port cover 31 and the torso cover 32 are attached to a stand 33 fixed to the inner peripheral surface of the rotating gantry 5. The vacuum duct D arranged inside the rotating gantry 5 is covered by the irradiation port cover 31 and the torso cover 32.

The stand 33 is formed by combining multiple metal frames. The vacuum duct D and the scanning electromagnet 11 are supported by the stand 33.

A dose monitor 34, a position monitor 35, and a range shifter 36 are provided below the beam extraction unit 30. The dose monitor 34 is a device that measures the dose of the particle beam B emitted from the beam extraction unit 30. The position monitor 35 is a device that measures the position of the particle beam B emitted from the beam extraction unit 30. The range shifter 36 is a device that adjusts the flight distance (stop position) of the particle beam B. In other words, the range shifter 36 adjusts the position where the Bragg peak occurs in the depth direction inside the body of the patient P.

The dose monitor 34 is filled with a gas that is ionized when the particle beam B passes through it. An electrode and a wire are provided in the space filled with this gas. When the particle beam B passes through the dose monitor 34, the gas is ionized and a current flows between the electrode and the wire. This principle is used to measure the intensity of the particle beam B.

The inside of the position monitor 35 is also filled with a gas that is ionized by the passage of the particle beam B. The gas is ionized by the particle beam B, and the passing position of the particle beam B is measured by utilizing the principle that a current flows between an electrode and a wire.

Inside the irradiation port 10, below the portion where the dose monitor 34, the position monitor 35, and the range shifter 36 are provided, a first energy modulation unit 41 and a second energy modulation unit 42 are provided. The first and second energy modulation units 41 and 42 are members for expanding the range in which the Bragg peak of the passing particle beam B occurs in the direction of beam travel.

In the first embodiment, the scanning electromagnet 11, the dose monitor 34, the position monitor 35, the range shifter 36, the second energy modulation unit 42, and the first energy modulation unit 41 are arranged in this order from the upstream side to the downstream side of the particle beam B. In other words, the first energy modulation unit 41 is provided at a position closest to the patient P. Note that the upstream side of the particle beam B is the side away from the patient P, and the downstream side of the particle beam B is the side close to the patient P. For example, in FIG. 3, the upper side of the paper is the upstream side.

The first and second energy modulation units 41, 42 are provided downstream of the components related to irradiation, including the scanning electromagnet 11, the dose monitor 34, the position monitor 35, and the range shifter 36. In other words, no components related to irradiation are located downstream of the first and second energy modulation units 41, 42. Note that the components related to irradiation refer to components related to the control or measurement of the particle beam B.

The first and second energy modulation sections 41, 42 in the first embodiment are made of flat ridge filters. These first and second energy modulation sections 41, 42 are square in plan view (see FIG. 7). Note that ridge filters are sometimes called mini-ridge filters or ripple filters, but these terms are synonymous.

The first energy modulation unit 41 is always positioned on the orbit of the particle beam B when the particle beam B is irradiated. The second energy modulation unit 42 is movable between a position where it is retracted from the orbit of the particle beam B and a position where it overlaps with the first energy modulation unit 41. In other words, the second energy modulation unit 42 is replaceable. In the first embodiment, the position where the particle beam B is retracted is outside the irradiation port cover 31.

As shown in FIG. 8, the first and second energy modulation sections 41, 42 serving as ridge filters have multiple ridge bars 43 formed on their surfaces. These ridge bars 43 are mountain-shaped (triangular) in side view and extend linearly in plan view. The multiple ridge bars 43 are arranged so as to be parallel to each other in plan view. In other words, the multiple ridge bars 43 are arranged periodically in one dimensional direction. Note that in FIG. 8, the ridge bars 43 are shown enlarged to aid understanding.

The width dimension R1 of the ridge bar 43 needs to be formed to be sufficiently small. The width dimension R1 of this ridge bar 43 is formed to be equal to or smaller than the beam diameter of the particle beam B. For example, when the beam diameter dimension of the particle beam B is 1 mm, the width dimension R1 of the ridge bar 43 is formed to be equal to or smaller than 1 mm. Note that the width dimension R1 of the ridge bars 43 of the first and second energy modulation sections 41, 42 may be different from each other.

As shown in FIG. 9, one ridge bar 43 has multiple steps 44 formed thereon, forming a mountain shape in side view. By forming these ridge bars 43, the ridge filter has thick mountain portions and thin valley portions.

For example, the energy of particle beam B1 that passes through the peaks is attenuated more than that of particle beam B2 that passes through the valleys. In other words, within the body of patient P, particle beam B1 that passes through the peaks is stopped at a shallower position than particle beam B2 that passes through the valleys. In this way, the ridge filter can change the distribution of energy of particle beam B by varying the thickness at each portion due to the ridge bar 43.

Figure 12 is a graph showing the relationship between dose and depth given to the body tissue of patient P by irradiation with particle beam B. The vertical axis shows the relative dose normalized based on the dose based on particle beam B, and the horizontal axis shows the depth from the body surface of patient P. In this graph, the solid line shows particle beam B irradiated using a ridge filter, and the dotted line shows particle beam B irradiated without using a ridge filter. The particle beam B is irradiated toward the affected area K located in a predetermined depth range Q1 inside the body of patient P.

As shown by the dotted line graph, the depth range Q2 in which the Bragg peak occurs, or in other words the width, is narrow for particle beam B when it does not pass through the ridge filter. In contrast, as shown by the solid line graph, the depth range Q2 in which the Bragg peak occurs is wider for particle beam B when it passes through the ridge filter. In other words, when particle beam B passes through the ridge filter, the Bragg peak is broadened.

When the width of the Bragg peak is narrow, multiple irradiations must be performed when irradiating the particle beam B over the entire range Q1 of the affected area K. In contrast, by broadening the Bragg peak using a ridge filter, a Bragg peak can be generated over a wide range with a single irradiation, so the number of irradiations of the particle beam B can be reduced. In other words, the irradiation time of the particle beam B can be shortened. Furthermore, errors in the irradiation position can be mitigated.

Specifically, as shown in FIG. 13, when irradiating the particle beam B, multiple slice planes 80 arranged in the depth direction of the body are set on the affected area K. The particle beam B is then sequentially irradiated with the output corresponding to each slice plane 80. A ridge filter is selected to correspond to the spacing between the slice planes 80, and the Bragg peak width of the particle beam B is set. In other words, a ridge filter is set for each affected area K to be irradiated.

As shown in FIG. 14, when the particle beam B is irradiated onto the slice surface 80, the irradiation spot 81 is scanned along the slice surface 80. The position of the irradiation spot 81 is sequentially changed by this scanning, so that the energy of the particle beam B is imparted to the entire slice surface 80. Furthermore, by irradiating the particle beam B onto all slice surfaces 80, the energy of the particle beam B is imparted to the entire affected area K.

As shown in FIG. 9, the height dimension R2 and width dimension R3 of each step 44 in the ridge bar 43 do not have to be constant, but are appropriately set in accordance with the Bragg peak generated by the particle beam B. The height dimension R2 and width dimension R3 of each step 44 are set so that the dose of the passing particle beam B exhibits a Gaussian distribution.

The relationship between the energy modulation units 41, 42 and the graphs of Gaussian distributions 91, 92 will be explained using Figures 17, 18, and 19. The horizontal axis of the graphs indicates the depth direction. Here, as shown in Figure 17, the first energy modulation unit 41 is set so that the dose of the particle beam B shows a Gaussian distribution 91 even when used alone. When the first energy modulation unit 41 is used alone, an energy distribution 95 that actually approximates the Gaussian distribution 91 is generated by the Bragg peaks 93 corresponding to each of the steps 44.

As shown in FIG. 18, when the second energy modulation section 42 is used alone, an energy distribution 96a is generated by the Bragg peaks 94a corresponding to each of the steps 44, but because the spacing between adjacent peaks is wide, the energy distribution 96a is not smooth. In other words, the energy distribution 96a does not approximate a Gaussian distribution 92.

As shown in FIG. 19, the second energy modulation unit 42 is set to have the dose of the particle beam B exhibit a Gaussian distribution 92 when used in combination with the first energy modulation unit 41. In other words, the first energy modulation unit 41 compensates for the widening of the Bragg peak formed by the second energy modulation unit 42 by widening the Bragg peak of the particle beam B passing through it. In this way, a Bragg peak of the required width can be generated. When two energy modulation units 41, 42 are used, the Bragg peak 94b actually generates an energy distribution 96b that is close to the Gaussian distribution 92.

For example, if the required Bragg peak widths are 1 mm, 2 mm, 3 mm, and 4 mm, the first energy modulation unit 41 that is always placed in the irradiation port 10 corresponds to the smallest width of 1 mm. Here, by appropriately replacing the three types of second energy modulation units 42, it is possible to accommodate any of the Bragg peak widths of 1 mm, 2 mm, 3 mm, and 4 mm.

When forming the ridge bar 43 on the ridge filter, the surface of the flat plate that is the base of the ridge filter is cut with a drill to form each step 44. In other words, the ridge bar 43 is formed by a cutting process. The ridge bar 43 is a very small part with a width and height of only a few millimeters, and requires precision, so the higher the ridge bar 43, the more difficult it is to process.

Specifically, the Bragg peak, which varies depending on the configuration of the ridge bar 43, differs depending on the dimensions of each step 44. Here, the relationship between the dimensions of the steps 44a, 44b and the Bragg peak will be explained with reference to Figures 15 and 16. Figure 15 shows the steps 44a, 44b of the ridge bar 43, which have different dimensions. Figure 16 shows the Bragg peaks corresponding to the steps 44a, 44b. The horizontal axis of this graph indicates the depth direction.

As shown in FIG. 15, a step 44a having the highest height dimension R6 and a step 44b having a lower height dimension R7 are illustrated. The dimensions of each step 44a, 44b are appropriately set according to the target Bragg peaks 83, 84.

Figure 16 shows a graph of Bragg peak 82 when a ridge filter is not used, Bragg peak 83 when passing through high step 44a, and Bragg peak 84 when passing through low step 44b. As shown in this graph, Bragg peak 84 when passing through low step 44b is displaced to a shallower position than Bragg peak 82 when a ridge filter is not used. Furthermore, Bragg peak 83 when passing through high step 44a is displaced to an even shallower position. Thus, in order to generate a specified Gaussian distribution 90, it is necessary to set these Bragg peaks 83, 84 appropriately.

As shown in FIG. 15, the width dimension R8 of the high step 44a must be narrower than the width dimension R9 of the low step 44b. In other words, the width dimension R8 of the step 44a narrows as the height dimension R6 increases. Therefore, the higher the ridge bar 43, the more difficult it is to process it.

As shown in FIG. 10, the height dimension R4 of the ridge bar 43 of the first energy modulation section 41 is lower than the height dimension R5 of the ridge bar 43 of the second energy modulation section 42. In this way, the machining precision of the ridge bar 43 can be maintained. In addition, the height dimensions R4 and R5 of the ridge bar 43 of the first energy modulation section 41 and the ridge bar 43 of the second energy modulation section 42 can be suppressed. For example, when widening the Bragg peak of the particle beam B, it is necessary to make the ridge bar 43 tall, but if the ridge bar 43 is made tall, it becomes elongated and difficult to machine. In this embodiment, by using two ridge filters and suppressing the height dimensions R4 and R5 of each ridge bar 43, the machining precision of the ridge bar can be maintained while widening the Bragg peak.

In the first embodiment, the first energy modulation unit 41 has a property that it can widen the Bragg peak by itself. In this way, the first energy modulation unit 41 can be used by itself to widen the Bragg peak. In addition, the second energy modulation unit 42 has a property that it cannot widen the Bragg peak by itself, but can widen the Bragg peak by overlapping with the first energy modulation unit 41. In this way, since there is no need to use the second energy modulation unit 42 by itself, the machining accuracy of the second energy modulation unit 42 can be lowered compared to when it is used by itself, thereby reducing costs. Furthermore, the combination of the first energy modulation unit 41 and the second energy modulation unit 42 can be simplified, and the replacement procedure for the second energy modulation unit 42 can be simplified, and the device can be simplified.

For example, when the second energy modulation unit 42 is used alone, changing from a given Bragg peak width to another Bragg peak width requires a two-step procedure of removing the first energy modulation unit 41 and incorporating the second energy modulation unit 42 instead. On the other hand, in the first embodiment, a similar change can be made in a single step of leaving the first energy modulation unit 41 as is and incorporating the second energy modulation unit 42.

Furthermore, for example, when the second energy modulation unit 42 is used alone, there is a possibility that the first energy modulation unit 41 may be removed, and therefore a mechanism for inserting and retracting the corresponding parts is required. On the other hand, in the first embodiment, it is sufficient to have a mechanism for inserting and retracting the corresponding part only for the second energy modulation unit 42, and the number of parts can be reduced.

The first and second energy modulation sections 41, 42 in the first embodiment are made of ridge filters made of aluminum. In this way, the first and second energy modulation sections 41, 42 can be made thin.

The first and second energy modulation sections 41 and 42 may be ridge filters made of acrylic. This makes fabrication easier, and reduces the manufacturing costs of the first and second energy modulation sections 41 and 42.

The ridge bar 43 of the ridge filter of the first embodiment has a mountain shape (isosceles triangle shape) in side view, but the ridge bar 43 may have a shape other than a mountain shape as long as the thickness of each part of the ridge filter is made different. For example, the ridge bar may have a semicircular shape, a right-angled triangle shape, a square shape, or a trapezoid shape.

As shown in FIG. 11, the first and second energy modulation units 41, 42 are arranged one above the other, but the orientation of each ridge bar 43 is arranged to differ by 90°. For example, of the four axes (X direction, -X direction, Y direction, -Y direction) extending in all directions in the radial direction of the beam with the particle beam B at the center, when the ridge bar 43 of the first energy modulation unit 41 extends along the Y axis, the ridge bar 43 of the second energy modulation unit 42 extends along the X axis. In other words, the ridge bars 43 of the first and second energy modulation units 41, 42 intersect with each other in a planar view. In this way, the dose of the passing particle beam B shows an appropriate Gaussian distribution.

As shown in FIG. 4, the irradiation port cover 31 has a U-shape in cross section, and the first energy modulation unit 41 is disposed at the bottom of the U-shape. The first energy modulation unit 41 is provided on the back surface of the bottom of the irradiation port cover 31, that is, on the surface that is not visible to the patient P.

A connection part 37 that holds the edge of the first energy modulation part 41 is formed on the back surface of the irradiation port cover 31. This connection part 37 allows the first energy modulation part 41 to be provided in correspondence with the part of the irradiation port cover 31 that is closest to the patient P. The first energy modulation part 41 may be fixed to the connection part 37 using a screw. The connection part 37 serves as a position determination part that determines the position of the first energy modulation part. In this way, the first energy modulation part 41 can be provided in a position that corresponds to the irradiation port cover 31.

The connection portion 37 as the position determination portion in the first embodiment forms an engagement piece that engages with the edge of the first energy modulation portion 41. In other words, the position determination portion is a portion of the irradiation port cover 31 that forms a shape in which the first energy modulation portion 41 is disposed. In this way, the first energy modulation portion 41 is disposed on the irradiation port cover 31, so that the position of the first energy modulation portion 41 can be accurately determined.

The ridge filter has a secondary property of scattering the particle beam B. Here, scattering refers to the expansion of the diameter of the particle beam B. When the particle beam B is scattered, its diameter increases as it moves away from the ridge filter downstream. In contrast, in the first embodiment, the position of the first energy modulation unit 41 is approximately the same as the part of the irradiation port cover 31 that is closest to the patient P, so that it is possible to minimize the radial expansion of the particle beam B while expanding the Bragg peak of the particle beam B. In other words, it is possible to improve the dose concentration on the affected area K.

In the first embodiment, the multiple energy modulation units 41, 42 are arranged side by side along the trajectory of the particle beam B, but it is sufficient that at least one energy modulation unit 41 is provided corresponding to the irradiation port cover 31. In this way, the multiple energy modulation units 41, 42 can correspond to the target Bragg peak, making it easier to manufacture the individual energy modulation units 41, 42.

The first energy modulation unit 41 is supported by the irradiation port cover 31. The irradiation port cover 31 is detachably attached to the stand 33 using a predetermined connecting tool. During maintenance, when installing or replacing the first energy modulation unit 41, the irradiation port cover 31 is removed from the stand 33 before the work is performed. The first energy modulation unit 41 is detachably supported by the stand 33 together with the irradiation port cover 31. In this way, the first energy modulation unit 41 can be attached and detached together with the irradiation port cover 31, so that maintenance work on the first energy modulation unit 41 can be easily performed.

The first energy modulation unit 41 is fixedly disposed on the irradiation port cover 31 and is a component that does not need to be replaced for each patient P. In other words, the first energy modulation unit 41 is a component that is always disposed on the trajectory of the particle beam B when the particle beam B is irradiated, regardless of the Bragg peak width required for the affected area K. In contrast, the second energy modulation unit 42 is a component that can be replaced depending on the Bragg peak width required for the affected area K.

As shown in Figures 4 and 6, an opening 38 is provided on the right side of the irradiation port cover 31 when viewed from the back. The vertical dimension M1 and horizontal dimension M2 (opening dimensions) of this opening 38 are dimensions that allow the second energy modulation unit 42 to pass through. In this way, the second energy modulation unit 42 can be inserted and removed from the irradiation port cover 31 through the opening 38 without removing the irradiation port cover 31 during maintenance.

A guide section 45 that guides the insertion and withdrawal of the second energy modulation section 42 is provided inside the irradiation port cover 31. A moving holding section 46 that holds at least a part of the guide section 45 and moves the guide section 45 in and out of the opening 38 is also provided. The moving holding section 46 is fixed to the stand 33. The guide section 45 is held movably relative to the moving holding section 46. The moving holding section 46 is a rail that extends horizontally, and the guide section 45 is movable horizontally along this rail.

When the guide unit 45 is stored inside the irradiation port cover 31, the portion where the second energy modulation unit 42 is placed is the placement unit 47 (connection unit). This placement unit 47 is provided at a position on the trajectory of the particle beam B. The guide unit 45 moves the second energy modulation unit 42 between a position on the trajectory of the particle beam B (placement unit 47) and a position where it is retracted from this trajectory.

When the guide section 45 is stored inside the irradiation port cover 31, it is fixed by a predetermined fixing mechanism provided in the moving holder 46. Therefore, even if the irradiation port 10 tilts with the rotation of the rotating gantry 5, the guide section 45 can be maintained in a fixed state relative to the frame 33.

The irradiation port cover 31 is provided with a lid portion 39 that closes the opening 38. When the guide portion 45 is inserted or removed, the lid portion 39 is opened. In this embodiment, a lid drive unit 51 that opens and closes the lid portion 39 and a guide drive unit 52 that drives the guide portion 45 are provided (see FIG. 20).

As shown in Figs. 4 and 6, an operating unit 40 is provided near the opening 38 of the irradiation port cover 31. When an operator operates this operating unit 40, the cover unit 39 or the guide unit 45 is driven. In addition, a latch unit 48 (connection unit) that restrains the second energy modulation unit 42 is provided on the guide unit 45. In this embodiment, a latch drive unit 53 that drives the latch unit 48 is provided (see Fig. 20). When an operator operates the operating unit 40, the second energy modulation unit 42 can be automatically restrained and released by the latch unit 48. In this way, a maintenance worker can release the restraint of the latch unit 48 from outside the irradiation port cover 31, improving maintainability.

The latch section 48 clamps the second energy modulation section 42 from above and below, and restrains multiple points of the second energy modulation section 42. In this way, even if the irradiation port 10 is turned upside down by the rotation of the rotating gantry 5, the second energy modulation section 42 can remain fixed to the guide section 45.

It should be noted that the entire second energy modulation unit 42 does not need to be pulled out from the opening 38, but only a portion of the second energy modulation unit 42 needs to be pulled out from the opening 38. Also, an operator may insert his or her hand through the opening 38 to access the second energy modulation unit 42 and perform the attachment/detachment work.

As shown in Figs. 5 and 7, when the second energy modulation unit 42 arranged in the arrangement section 47 is replaced with a replacement second energy modulation unit 42', the operator operates the operation section 40 to drive the lid section 39 and automatically open the opening 38. Furthermore, the guide section 45 is driven to automatically pull out the second energy modulation unit 42 from the opening 38. The operator then operates the operation section 40 to release the latch section 48 and remove the second energy modulation unit 42 from the guide section 45. Thereafter, the replacement second energy modulation unit 42' is attached to the guide section 45, and the latch section 48 again restrains the second energy modulation unit 42. The operator then operates the operation section 40 to automatically return the guide section 45 to the inside of the irradiation port cover 31, and the opening 38 is closed by the lid section 39.

In the first embodiment, the guide section 45 moves along the moving holder 46, so the worker can easily insert and remove the second energy modulation section via this guide section 45.

The stand 33 is provided with a position detection sensor 54 that detects that the guide section 45 is in a fixed position. In other words, the position detection sensor 54 can confirm that the second energy modulation section 42 has been placed in the placement section 47. The latch section 48 is also provided with a latch sensor 55 that detects that the second energy modulation section 42 is appropriately restrained.

In the first embodiment, the latch sensor 55 confirms that the second energy modulation unit 42 is appropriately restrained, and the position detection sensor 54 confirms that the second energy modulation unit 42 is placed in the placement section 47.

When the second energy modulation unit 42 is placed in the placement section 47, the second energy modulation unit 42 is restrained by the latch section 48, so that the second energy modulation unit 42 does not become misaligned from the placement section 47.

A first tag 56 is attached to the first energy modulation unit 41, and a second tag 57 is attached to the second energy modulation unit 42. These first and second tags 56, 57 are composed of RFID tags. These first and second tags 56, 57 store identification information that can identify the respective energy modulation units 41, 42. Furthermore, the stand 33 is provided with a non-contact first tag reader 58 that reads the first tag 56, and a non-contact second tag reader 59 that reads the second tag 57.

The second energy modulation unit 42 is a component that is replaced depending on the depth position of the affected area K. Therefore, by reading the identification information of the second tag 57, it is possible to confirm whether or not the appropriate second energy modulation unit 42 has been set. By this confirmation, even if the operator sets the wrong second energy modulation unit 42, a specified notification can be issued to notify the operator. It is also possible to confirm whether or not the appropriate first energy modulation unit 41 has been set by reading the identification information of the first tag 56.

In the first embodiment, the second energy modulation unit 42 is inserted and removed from the inside of the irradiation port cover 31 through the opening 38 in only one direction. The direction in which the second energy modulation unit 42 is inserted and removed is referred to as the specific direction. In other words, the opening 38 is opened in a portion of the irradiation port cover 31 that corresponds to the specific direction. In this way, the replacement work of the second energy modulation unit 42 can be easily performed without removing the irradiation port cover 31 from the stand 33, and the replacement work can be simplified, thereby improving maintainability.

In the first embodiment, the second energy modulation unit 42 can be inserted and retracted along a specific direction corresponding to one of four axes extending in all directions in the radial direction of the beam with the particle beam B at the center. For example, as shown in FIG. 11, of the four axes (X direction, -X direction, Y direction, -Y direction) extending in all directions in the radial direction of the beam with the particle beam B at the center, if the Y direction is the front of the irradiation port cover 31 and the -Y direction is the rear of the irradiation port cover 31, the specific direction is only the X direction. In other words, the second energy modulation unit 42 is inserted and retracted along one specific direction with respect to the placement unit 47.

In this way, the distance traveled when inserting and retracting the second energy modulation unit 42 can be shortened. In addition, since the second energy modulation unit 42 is accessible only from one side of the irradiation port cover 31, the irradiation port cover 31 can be made smaller.

As shown in FIG. 3, when the opening 38 is closed, the outer surface of the cover 39 is flush with the outer surface of the irradiation port cover 31. This makes the opening 38 less noticeable, improving the appearance of the irradiation port cover 31.

The opening 38 is provided on a side surface of the irradiation port cover 31 other than the surface facing the treatment table 13. In other words, the opening 38 is provided on a side surface of the irradiation port cover 31 other than the bottom surface. In this way, the opening 38 is not visible to the patient P placed on the treatment table 13, improving the appearance of the irradiation port cover 31. Note that the opening 38 is not provided on the front or back surface of the irradiation port cover 31.

As shown in Figures 2 and 3, when the surface visible in the line of sight G2 along the rotation axis J from one end of the rotating gantry 5 is defined as the front of the irradiation port cover 31, the opening 38 is provided on a side other than the front. In this way, when the patient P looks at the irradiation port cover 31 from the entrance side of the treatment space 12, the opening 38 is not visible, improving the appearance of the irradiation port cover 31.

The opening 38 is provided on a side of the irradiation port cover 31 other than the side facing the rotation axis J. In this way, the opening 38 is not visible in the line of sight G2 when the irradiation port cover 31 is viewed from the patient P who is placed on the treatment table 13 and at the rotation axis J, and therefore the appearance of the irradiation port cover 31 can be improved. In addition, a structure reminiscent of a machine, such as the opening 38, can be made invisible to the patient P, which prevents the patient P from feeling oppressive.

As shown in Figures 3 and 11, the second energy modulation unit 42 is disposed upstream of the first energy modulation unit 41 in the traveling direction of the particle beam B. In this way, the first energy modulation unit 41, which mainly sets the broadening of the Bragg peak, is located close to the patient P, so that the radial broadening of the particle beam B can always be suppressed.

A scanning electromagnet 11 is disposed upstream of the first and second energy modulation sections 41, 42. The area N1 of the first energy modulation section 41 is larger than the area N2 of the second energy modulation section 42. The particle beam B is caused to oscillate laterally by the scanning electromagnet 11 while scanning the affected area K.

In the first embodiment, the area N1 of the first energy modulation section 41 is larger than the area N2 of the second energy modulation section 42, so that the areas N1 and N2 of the energy modulation sections 41 and 42 can be set according to the scanning range of the particle beam B.

Next, the system configuration of the particle beam therapy device 1 will be described with reference to the block diagram shown in FIG. 20.

As shown in FIG. 20, the particle beam therapy device 1 includes an irradiation control system 50 that controls the irradiation port 10. The irradiation control system 50 is realized by the CPU executing a program stored in the memory or HDD.

The irradiation control system 50 includes a scanning electromagnet 11, a dose monitor 34, a position monitor 35, a range shifter 36, an operation unit 40, a lid drive unit 51, a guide drive unit 52, a latch drive unit 53, a position detection sensor 54, a latch sensor 55, a first tag reader 58, a second tag reader 59, an alarm output unit 60, a setting memory unit 61, a placement determination unit 62, a tag determination unit 63, and an irradiation control unit 64.

The notification output unit 60 issues a predetermined notification when the second energy modulation unit 42 is replaced. This notification output unit 60 may be a display that displays notification information, or a speaker that outputs a notification sound. The notification output unit 60 is provided in the irradiation port 10. The notification output unit 60 may also be provided in the control computer in the control room where the engineer is located.

The setting storage unit 61 stores setting information related to the patient P and the affected area K that is necessary for particle beam therapy. This setting information includes information related to the position and range of the affected area K, information related to the dose to be irradiated to the affected area K, and information related to the first and second energy modulation units 41, 42. The setting storage unit 61 is provided in a control computer in a control room. The setting information is input to the setting storage unit 61 before starting particle beam therapy, particularly before performing replacement work on the second energy modulation unit 42.

The placement determination unit 62 determines whether or not the second energy modulation unit 42 is placed in the placement unit 47 based on detection by the position detection sensor 54 and the latch sensor 55. This determination result is sent to the irradiation control unit 64. In this way, it is possible to know whether or not the second energy modulation unit 42 is placed in the placement unit 47.

The tag determination unit 63 determines whether or not the appropriate tags 56, 57 have been read by the tag reading units 58, 59 based on the identification information read by the tag reading units 58, 59. This determination result is sent to the irradiation control unit 64. The tag determination unit 63 makes a determination by comparing it with the setting information previously stored in the setting storage unit 61.

The irradiation control unit 64 controls each device of the irradiation port 10. This irradiation control unit 64 controls the scanning electromagnet 11 and the range shifter 36. The irradiation control unit 64 obtains information indicating the control result of the particle beam B from the scanning electromagnet 11.

The irradiation control unit 64 also acquires information about the particle beam B from the dose monitor 34 and the position monitor 35. Furthermore, the irradiation control unit 64 controls the notification output unit 60 when issuing a specified notification.

The irradiation control unit 64 also acquires setting information from the setting storage unit 61. Furthermore, during or after the particle beam therapy, the irradiation control unit 64 stores information related to the treatment and information related to various flags in the setting storage unit 61.

The operation unit 40 controls the lid drive unit 51, the guide drive unit 52, and the latch drive unit 53. The irradiation control unit 64 acquires information related to the drive of the lid unit 39 and the guide unit 45 from the operation unit 40. The operation unit 40 also acquires information from the irradiation control unit 64 as to whether or not particle beam therapy is stopped, that is, whether or not it is safe to drive the lid unit 39 and the guide unit 45.

Although not shown in the figure, the particle beam therapy device 1 includes an accelerator control system that controls the beam generator 2, the circular accelerator 3, and the beam transport line 4, a gantry control system that controls the rotating gantry 5, and a treatment table control system that controls the treatment table 13. The irradiation control unit 64 of the irradiation control system 50 controls the irradiation port 10 while exchanging control information bidirectionally with each of the accelerator control system, the gantry control system, and the treatment table control system.

The system of the present embodiment is configured with a computer having hardware resources such as a CPU, a ROM, a RAM, and a HDD, and the CPU executes various programs to realize software-based information processing using the hardware resources. Furthermore, the method of operating the particle beam therapy device 1 of the present embodiment is realized by having the computer execute the programs.

Next, the replacement process of the second energy modulation unit 42 executed by the irradiation control system 50 will be described with reference to the flowcharts in Figs. 21 and 22. Note that the block diagram in Fig. 20 will be referred to as appropriate.

As shown in FIG. 21, first, in step S11, the irradiation control unit 64 determines whether the particle beam therapy device 1 is stopped. That is, it determines whether the beam generator 2, the circular accelerator 3, the beam transport line 4, and the rotating gantry 5 are stopped. Here, if the particle beam therapy device 1 is not stopped (step S11 is NO), the replacement process of the second energy modulation unit 42 is terminated. On the other hand, if the particle beam therapy device 1 is stopped (step S11 is YES), the process proceeds to step S12.

In the next step S12, the operator inputs setting information into the setting storage unit 61. Here, setting information related to the replacement second energy modulation unit 42' is input. Note that the setting information may be input automatically at a predetermined timing from a higher-level system.

In the next step S13, the operation unit 40 determines whether or not the opening 38 has been opened. If the worker has not performed the opening operation using the operation unit 40 (step S13 is NO), the replacement process for the second energy modulation unit 42 ends. On the other hand, if the worker has performed the opening operation using the operation unit 40 (step S13 is YES), the process proceeds to step S14.

In the next step S14, the operation unit 40 drives the lid unit 39 via the lid drive unit 51 to open the opening 38.

In the next step S15, the operation unit 40 drives the guide unit 45 by the guide drive unit 52, causing the guide unit 45 to protrude outward from the opening 38, and pulls out the second energy modulation unit 42 from the irradiation port cover 31. At this time, the guide unit 45 retracts the second energy modulation unit 42 from the placement unit 47 along a specific direction. In other words, the second energy modulation unit 42 moves to a position where it is retracted from the orbit of the particle beam B.

In the next step S16, the operation unit 40 drives the latch unit 48 via the latch drive unit 53, and releases the constraint on the second energy modulation unit 42.

In the next step S17, with the latch unit 48 released, the worker replaces the second energy modulation unit 42. In other words, the worker can access the second energy modulation unit 42 through the opening 38. Here, when the worker has finished replacing the second energy modulation unit 42, he or she performs a completion operation using the operation unit 40.

In the next step S18, the operation unit 40 drives the latch unit 48 by the latch drive unit 53 to restrain the second energy modulation unit 42. When the second energy modulation unit 42 is restrained by the latch unit 48, this is detected by the latch sensor 55.

In the next step S19, the operation unit 40 drives the guide unit 45 by the guide drive unit 52, inserts the guide unit 45 into the opening 38, and pulls in the second energy modulation unit 42 inside the irradiation port cover 31. At this time, the guide unit 45 inserts the second energy modulation unit 42 into the placement unit 47 along a specific direction. In other words, the second energy modulation unit 42 moves to a position where it overlaps with the first energy modulation unit 41 and is on the trajectory of the particle beam B.

In the next step S20, when the second energy modulation unit 42 is placed in the placement unit 47, that is, when the guide unit 45 is moved to a fixed position, this is detected by the position detection sensor 54. At this time, the second energy modulation unit 42 is provided on the trajectory of the particle beam B.

In the next step S21, the operation unit 40 drives the lid unit 39 using the lid drive unit 51 to close the opening 38.

As shown in FIG. 22, in the next step S22, the first tag reader 58 reads the identification information of the first tag 56 of the first energy modulation unit 41 arranged on the irradiation port cover 31.

In the next step S23, the tag determination unit 63 compares the setting information related to the first energy modulation unit 41 stored in the setting storage unit 61 with the identification information of the first tag 56 read by the first tag reading unit 58, and determines whether the first energy modulation unit 41 is appropriate. If the first energy modulation unit 41 is not appropriate (NO in step S23), the process proceeds to step S31, where the notification output unit 60 issues an abnormality notification, and the process ends. On the other hand, if the first energy modulation unit 41 is appropriate (YES in step S23), the process proceeds to step S24.

In the next step S24, the irradiation control unit 64 determines whether or not the opening 38 is blocked by the lid 39. If the opening 38 is not blocked by the lid 39 (step S24 is NO), the process proceeds to step S31, where the notification output unit 60 issues an abnormality notification, and the process ends. On the other hand, if the opening 38 is blocked by the lid 39 (step S24 is YES), the process proceeds to step S25.

In the next step S25, the arrangement determination unit 62 determines whether or not the second energy modulation unit 42 is restrained by the latch unit 48 based on detection by the latch sensor 55. Here, if the second energy modulation unit 42 is not restrained by the latch unit 48 (step S25 is NO), the process proceeds to step S31, where the notification output unit 60 issues an abnormality notification, and the process ends. On the other hand, if the second energy modulation unit 42 is restrained by the latch unit 48 (step S25 is YES), the process proceeds to step S26.

In the next step S26, the placement determination unit 62 determines whether or not the second energy modulation unit 42 is placed in the placement unit 47 based on detection by the position detection sensor 54. If the second energy modulation unit 42 is not placed in the placement unit 47 (step S26 is NO), the process proceeds to step S31, where the notification output unit 60 issues an abnormality notification, and the process ends. On the other hand, if the second energy modulation unit 42 is placed in the placement unit 47 (step S26 is YES), the process proceeds to step S27.

In the next step S27, the second tag reading unit 59 reads the identification information of the second tag 57 of the second energy modulation unit 42 arranged in the placement unit 47.

In the next step S28, the tag determination unit 63 compares the setting information related to the second energy modulation unit 42 stored in the setting storage unit 61 with the identification information of the second tag 57 read by the second tag reading unit 59, and determines whether the second energy modulation unit 42 is appropriate. If the second energy modulation unit 42 is not appropriate (NO in step S28), the process proceeds to step S31, where the notification output unit 60 issues an abnormality notification, and the process ends. On the other hand, if the second energy modulation unit 42 is appropriate (YES in step S28), the process proceeds to step S29.

In the next step S29, the illumination control unit 64 issues a completion notification via the notification output unit 60 to notify the user that the replacement work has been completed successfully.

In the next step S30, the irradiation control unit 64 sets the irradiation permission flag and ends the process.

Next, the particle beam therapy process executed by the irradiation control system 50 will be described with reference to the flowchart in FIG. 23. Note that the block diagram in FIG. 20 will be referred to as appropriate.

As shown in FIG. 23, when particle beam therapy is started, first, in step S41, the irradiation control unit 64 determines whether or not the irradiation permission flag is set. Here, if the irradiation permission flag is not set (step S41 is NO), the process proceeds to step S52, where the notification output unit 60 issues a stop notification, and the process ends. On the other hand, if the irradiation permission flag is set (step S41 is YES), the process proceeds to step S42.

In the next step S42, the irradiation control unit 64 sends an irradiation permission signal to the accelerator control system and outputs the particle beam B.

In the next step S43, the irradiation control unit 64 adjusts the scanning direction of the particle beam B by the scanning electromagnet 11.

In the next step S44, the irradiation control unit 64 measures the dose of the particle beam B using the dose monitor 34 and determines whether the dose of the particle beam B is within a normal range. If there is an abnormality in the dose of the particle beam B (step S44 is NO), the irradiation control unit 64 stops the output of the particle beam B, proceeds to step S52, issues a stop notification by the notification output unit 60, and ends the process. On the other hand, if the dose of the particle beam B is within a normal range (step S44 is YES), the irradiation control unit 64 proceeds to step S45.

In the next step S45, the irradiation control unit 64 measures the position of the particle beam B using the position monitor 35, and determines whether the position of the particle beam B is within a normal range. If there is an abnormality in the position of the particle beam B (step S45 is NO), the output of the particle beam B is stopped, and the process proceeds to step S52, where the notification output unit 60 issues a stop notification, and the process ends. On the other hand, if the position of the particle beam B is within a normal range (step S45 is YES), the process proceeds to step S46.

In the next step S46, the irradiation control unit 64 adjusts the flight distance of the particle beam B using the range shifter 36.

In the next step S47, the particle beam B passes through the second energy modulation unit 42.

In the next step S48, the particle beam B passes through the first energy modulation unit 41.

In the next step S49, the particle beam B is irradiated toward the patient, and the particle beam B, whose Bragg peak has been broadened by the first and second energy modulation units 41 and 42, reaches the affected area K.

In the next step S50, the irradiation control unit 64 determines whether or not particle beam therapy has ended. If particle beam therapy has not ended (NO in step S50), the process returns to step S42 described above. On the other hand, if particle beam therapy has ended (YES in step S50), the process proceeds to step S51.

In the next step S51, the irradiation control unit 64 clears the irradiation permission flag and ends the process.

In the first embodiment, the particle beam B is irradiated only when the irradiation permission flag is set. In other words, irradiation of the particle beam B is permitted when it is determined in step S25 described above that the second energy modulation unit 42 is restrained by the latch unit 48. In this way, the particle beam B is not irradiated when the second energy modulation unit 42 is not restrained by the latch unit 48, thereby forming an interlock.

In addition, in step S26 described above, if it is determined that the second energy modulation unit 42 is placed in the placement unit 47, irradiation of the particle beam B is permitted. In this way, when the second energy modulation unit 42 is not placed in the placement unit 47, the particle beam B is not irradiated, so that an interlock can be configured.

Second Embodiment
Next, an irradiation port 10A of a particle beam therapy system 1A according to a second embodiment will be described with reference to Fig. 24. Note that the same components as those shown in the above-described embodiment are denoted by the same reference numerals, and duplicated descriptions will be omitted.

As shown in FIG. 24, in the second embodiment, the first energy modulation unit 41 is fixed to the stand 33. Also, the second energy modulation unit 42 is detachably attached to the rear surface of the bottom of the irradiation port cover 31A via the connection portion 37. That is, the second energy modulation unit 42 is provided below the first energy modulation unit 41. Note that in the second embodiment, the rear surface of the bottom of the irradiation port cover 31A serves as the placement portion 47. Also, the connection portion 37 of the irradiation port cover 31A serves as the position determination portion.

In this way, the second energy modulation unit 42 in the second embodiment is disposed downstream of the first energy modulation unit 41 in the traveling direction of the particle beam B. In the second embodiment, the opening 38 (see FIG. 4) is not provided on the side of the irradiation port cover 31A.

The area of the second energy modulation section 42 is larger than the area of the first energy modulation section 41. In this way, the areas of the energy modulation sections 41 and 42 can be adjusted according to the scanning range of the particle beam B.

When replacing the second energy modulation unit 42, the irradiation port cover 31A is removed from the stand 33. Then, the second energy modulation unit 42 is removed from the irradiation port cover 31A, and a replacement second energy modulation unit 42' is attached.

In the second embodiment, the second energy modulation unit 42 can be provided in the part of the irradiation port 10A that is closest to the patient P. In addition, since the second energy modulation unit 42 can be easily accessed from the downstream side in the traveling direction of the particle beam B, the replacement work of the second energy modulation unit 42 can be easily performed.

Third Embodiment
Next, an irradiation port 10B of a particle beam therapy system 1B according to a third embodiment will be described with reference to Fig. 25. Note that the same components as those shown in the above-described embodiment are denoted by the same reference numerals, and duplicated description will be omitted.

As shown in FIG. 25, in the third embodiment, the first energy modulation unit 41 is fixed to the stand 33. Furthermore, an opening 71 in which the second energy modulation unit 42 is disposed is provided at the bottom of the irradiation port cover 31B. In other words, the second energy modulation unit 42 is provided below the first energy modulation unit 41.

A connection part 37 to which the second energy modulation part 42 is detachably connected is provided on the edge of the opening 71 at the bottom of the irradiation port cover 31B. In the third embodiment, the opening 71 at the bottom of the irradiation port cover 31B serves as the placement part. Also, the connection part 37 of the irradiation port cover 31B serves as the position determination part.

In this way, the second energy modulation unit 42 in the third embodiment is disposed downstream of the first energy modulation unit 41 in the traveling direction of the particle beam B. Note that in the third embodiment, the opening 38 (see FIG. 4) is not provided on the side of the irradiation port cover 31B.

A decorative cover 72 is removably attached to the bottom surface of the irradiation port cover 31B. This decorative cover 72 can conceal the second energy modulation section 42, improving the appearance of the irradiation port 10B.

When replacing the second energy modulation unit 42, remove the decorative cover 72 from the irradiation port cover 31B. Then, remove the second energy modulation unit 42 from the opening 71 of the irradiation port cover 31B and attach a replacement second energy modulation unit 42'. After that, reattach the decorative cover 72.

In the third embodiment, when the second energy modulation unit 42 is positioned downstream of the first energy modulation unit 41 in the traveling direction of the particle beam B, the replacement work of the second energy modulation unit 42 can be performed without removing the irradiation port cover 31B.

Fourth Embodiment
Next, an irradiation port 10C of a particle beam therapy system 1C according to a fourth embodiment will be described with reference to Fig. 26. Note that the same components as those shown in the above-described embodiment will be denoted by the same reference numerals, and duplicated description will be omitted.

As shown in FIG. 26, in the fourth embodiment, the first energy modulation unit 41 is fixed to the pedestal 33. Furthermore, the second energy modulation unit 42 is fixed to the pedestal 33 below the first energy modulation unit 41. In other words, both the first and second energy modulation units 41, 42 are supported by the pedestal 33. Furthermore, an opening 73 is formed at the bottom of the irradiation port cover 31C. The lower end of the pedestal 33 is provided at a position corresponding to the opening 73.

A connection section 37 to which the second energy modulation section 42 is detachably connected is provided at the lower end of the pedestal 33. In the fourth embodiment, the lower end of the pedestal 33 serves as the placement section 47. The lower end of the pedestal 33 is set in correspondence with the position of the opening 73 of the irradiation port cover 31C. In other words, in the fourth embodiment, the opening 73 of the irradiation port cover 31C serves as the position determination section.

In this way, the second energy modulation unit 42 in the fourth embodiment is disposed downstream of the first energy modulation unit 41 in the traveling direction of the particle beam B. In the fourth embodiment, the opening 38 (see FIG. 4) is not provided on the side of the irradiation port cover 31C.

The irradiation port cover 31C is supported on the stand 33 via the body cover 32. A gap is formed between the edge of the opening 73 of the irradiation port cover 31C and the stand 33.

When replacing the second energy modulation unit 42, remove the second energy modulation unit 42 from the connection part 37 of the stand 33. Then, attach the replacement second energy modulation unit 42' to the connection part 37 of the stand 33.

In the fourth embodiment, the second energy modulation unit 42 is supported by the stand 33, so that the second energy modulation unit 42 can be firmly supported. In addition, the second energy modulation unit 42 can be easily accessed from the downstream side in the traveling direction of the particle beam B, so that the replacement work of the second energy modulation unit 42 can be easily performed. Furthermore, when the second energy modulation unit 42 is removed, the first energy modulation unit 41 can be accessed.

Fifth Embodiment
Next, an irradiation port 10D of a particle beam therapy system 1D according to a fifth embodiment will be described with reference to Fig. 27. Note that the same components as those shown in the above-mentioned embodiments are denoted by the same reference numerals, and duplicated descriptions will be omitted.

As shown in FIG. 27, in the fifth embodiment, the first energy modulation unit 41 is fixed to the stand 33. Furthermore, the second energy modulation unit 42 is detachably attached to the bottom surface of the irradiation port cover 31D via the connection portion 37. In other words, the second energy modulation unit 42 is provided below the first energy modulation unit 41. Note that in the fifth embodiment, the bottom surface of the irradiation port cover 31D serves as the placement portion 47. Furthermore, the connection portion 37 of the irradiation port cover 31D serves as the position determination portion.

In this way, the second energy modulation unit 42 in the fifth embodiment is disposed downstream of the first energy modulation unit 41 in the traveling direction of the particle beam B. Note that in the fifth embodiment, the opening 38 (see FIG. 4) is not provided on the side of the irradiation port cover 31D.

When replacing the second energy modulation unit 42, remove the second energy modulation unit 42 from the connection part 37 of the irradiation port cover 31D. Then, attach the replacement second energy modulation unit 42' to the connection part 37 of the irradiation port cover 31D.

In the fifth embodiment, the second energy modulation unit 42 is provided on the surface of the irradiation port cover 31D, making replacement easy.

Sixth Embodiment
Next, an irradiation port 10E of a particle beam therapy system 1E according to a sixth embodiment will be described with reference to Fig. 28. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals, and duplicated descriptions will be omitted.

As shown in FIG. 28, in the sixth embodiment, the first energy modulation unit 41E is provided on the back surface of the bottom of the irradiation port cover 31E. This first energy modulation unit 41E is attached to the irradiation port cover 31E by a connection unit 37. The second energy modulation unit 42 is provided on a guide unit 45 above the first energy modulation unit 41E. In other words, the first energy modulation unit 41E is disposed downstream of the second energy modulation unit 42 in the traveling direction of the particle beam B.

The first energy modulation unit 41E of the sixth embodiment is made of a porous block made of a porous material. This porous block has many fine cavities formed inside the synthetic resin. In other words, the inside of the porous block is a mottled arrangement of fine cavities and the material that makes up the block. The porous block has paths that pass through a small number of cavities and paths that pass through a large number of cavities. The path here refers to a straight line that passes through the first energy modulation unit 41E in the vertical direction from one surface to the other surface.

For example, the energy of the particle beam B that has passed through a path that passes through a small number of cavities is attenuated more than that of the particle beam B that has passed through a path that passes through a large number of cavities. In other words, within the body of the patient P, the particle beam B that has passed through a small number of cavities is stopped at a shallower position than the particle beam B that has passed through a large number of cavities. In this way, since the first energy modulation unit 41E is made of a porous block, the energy distribution of the particle beam B can be changed. This makes it possible to broaden the Bragg peak of the particle beam B.

The porous block is set so that the dose of the passing particle beam B exhibits a Gaussian distribution. The thickness T1 of the first energy modulation section 41E, which is made of a porous block, is greater than the thickness T2 of the second energy modulation section 42, which is made of a ridge filter.

In the sixth embodiment, the first energy modulation section is formed from a porous material, which makes it easier to manufacture the first energy modulation section 41E than when it is formed from a ridge filter.

In addition, the first energy modulation section 41E, which has a certain thickness, is fixed to the irradiation port cover 31E, and the second energy modulation section 42, which is thinner than this, is the subject of replacement work, thereby improving maintainability.

The porous block has the secondary property of scattering the particle beam B, but in the sixth embodiment, the position of the first energy modulation unit 41E is approximately the same as the part of the irradiation port cover 31E that is closest to the patient P, so that the Bragg peak of the particle beam B can be widened while the radial spread of the particle beam B can be suppressed.

Seventh Embodiment
Next, an irradiation port 10F of a particle beam therapy system 1F according to a seventh embodiment will be described with reference to Fig. 29. Note that the same components as those shown in the above-described embodiments are denoted by the same reference numerals, and duplicated descriptions will be omitted.

As shown in FIG. 29, the bottom of the irradiation port cover 31F is made of a porous material, and this portion serves as the first energy modulation section 41F. The bottom of the irradiation port cover 31F serves as the position determination section. The second energy modulation section 42, which is made of a ridge filter, is provided on the guide section 45 above the first energy modulation section 41F.

In the seventh embodiment, the first energy modulation section 41F is exposed, but since the irradiation port cover 31F and the first energy modulation section 41F are integrated, the first energy modulation section 41F can be made less noticeable. This improves the appearance of the irradiation port 10F.

Eighth embodiment
Next, an irradiation port 10G of a particle beam therapy system 1G according to an eighth embodiment will be described with reference to Fig. 30. Note that the same components as those shown in the above-described embodiment will be denoted by the same reference numerals, and duplicated description will be omitted.

As shown in FIG. 30, in the eighth embodiment, three guide parts 45 are provided inside the irradiation port cover 31G. A second energy modulation part 42 is provided on each guide part 45. In other words, the three second energy modulation parts 42 are arranged in a line in the vertical direction.

Inside the irradiation port cover 31G, arrangement sections 47 are provided corresponding to the respective second energy modulation sections 42. These arrangement sections 47 are positioned so as to overlap the first energy modulation sections 41 and compensate for the widening of the Bragg peak. Also, inside the irradiation port cover 31G, an evacuation section 74 is provided, which is a position for evacuation from the orbit of the particle beam B.

When the guide section 45 is driven, the second energy modulation section 42 is moved between the placement section 47 and the retraction section 74. In other words, multiple second energy modulation sections 42 can be placed inside the irradiation port cover 31G in advance, and the second energy modulation section 42 can be changed depending on the irradiation target.

A large opening 38 is provided on the side of the irradiation port cover 31G. This opening 38 is closed by a lid 39. By opening the opening 38, an operator can access each of the second energy modulation sections 42.

The guide portion 45 can be protruded to the outside from the opening 38 to perform replacement work of the second energy modulation portion 42. The three second energy modulation portions 42 are moved along the same specific direction by driving the guide portion 45. The opening 38 is formed corresponding to this specific direction.

In addition, the particle beam B may be irradiated with two or more second energy modulation units 42 arranged in the arrangement unit 47. Furthermore, the particle beam B may be irradiated with all the second energy modulation units 42 retracted to the retraction unit 74.

In the eighth embodiment, multiple second energy modulation units 42 are arranged inside the irradiation port cover 31G in advance, and the second energy modulation units 42 can be changed depending on the irradiation target, thereby improving maintainability.

The particle beam therapy device according to this embodiment has been described based on the first to eighth embodiments, but the configuration applied in any one of the embodiments may be applied to another embodiment, and the configurations applied in each embodiment may be combined.

In the flowchart of this embodiment, an example is shown in which each step is executed in series, but the order of steps is not necessarily fixed, and the order of some steps may be reversed. Also, some steps may be executed in parallel with other steps.

The system of this embodiment includes a control device that is a highly integrated processor such as a dedicated chip, FPGA (Field Programmable Gate Array), GPU (Graphics Processing Unit), or CPU (Central Processing Unit), a storage device such as ROM (Read Only Memory) or RAM (Random Access Memory), an external storage device such as HDD (Hard Disk Drive) or SSD (Solid State Drive), a display device such as a display, an input device such as a mouse or keyboard, and a communication interface. This system can be realized with a hardware configuration that uses a normal computer.

The program executed by the system of this embodiment is provided in advance in a ROM or the like. Alternatively, this program may be provided stored in an installable or executable file format on a non-transitory computer-readable storage medium such as a CD-ROM, CD-R, memory card, DVD, or flexible disk (FD).

The programs executed by this system may also be stored on a computer connected to a network such as the Internet and provided by downloading them via the network. This system may also be configured by combining separate modules that independently perform the functions of the components and connect them together via a network or dedicated lines.

In this embodiment, a facility that performs heavy ion cancer therapy is illustrated as an example, but this embodiment can also be applied to other facilities. For example, this embodiment can also be applied to a facility that performs proton cancer therapy.

In addition, the position determination portion in this embodiment may be the connection portion 37 with the energy modulation portions 41 and 42, or the openings 71 and 73 in which the energy modulation portions 41 and 42 are disposed, or the portion where the energy modulation portions 41 and 42 are indirectly connected to the irradiation port cover 31 via an attachment jig.

In addition, multiple first energy modulation units 41 may be used in a stacked manner to widen the Bragg peak of the particle beam B. Also, multiple second energy modulation units 42 may be used in a stacked manner to widen the Bragg peak of the particle beam B.

In addition, the Bragg peak of the particle beam B may be broadened using only the first energy modulation unit 41 without using the second energy modulation unit 42.

In this embodiment, the term "access" includes a situation in which an operator can touch the energy modulation unit 42. For example, "access" also includes a situation in which an operator can touch the energy modulation unit 42 without moving the energy modulation unit 42 to the outside of the irradiation port cover 31. In addition, the term "access" also includes a situation in which an operator can get close to and see the energy modulation unit 42.

The particle beam therapy device 1 of this embodiment is equipped with a rotating gantry 5, but the particle beam therapy device may not be equipped with a rotating gantry 5 and may instead be equipped with a fixed irradiation chamber in which the irradiation port 10 is fixedly arranged.

A frame that holds the energy modulation unit 42 may be provided, and the energy modulation unit 42 and the frame may form a cartridge-type replacement device that is detachable from the opening 38. A lid 39 that closes the opening 38 may be integrally provided with the frame, and the lid 39 may be detachable from the opening 38 together with the frame.

In this embodiment, whether or not appropriate energy modulation units 41, 42 are arranged is determined based on the identification information stored in tags 56, 57. However, whether or not appropriate energy modulation units 41, 42 are arranged may be determined using a configuration other than tags 56, 57. For example, differently shaped projections and recesses may be provided on the edges of energy modulation units 41, 42, and the shape of the projections and recesses may be read to determine whether or not appropriate energy modulation units 41, 42 are arranged.

In this embodiment, the particle beam B travels through the airless vacuum duct D so that the particle beam B is not scattered by the air, but the inside of the vacuum duct D does not necessarily have to be a vacuum. For example, the vacuum duct D may contain helium gas, which scatters the particle beam B relatively little.

In this embodiment, a lid drive unit 51 is provided to open and close the lid unit 39, but the lid unit 39 may be a flap type that opens and closes in response to the movement of the guide unit 45. Also, the lid unit 39 may be a push type that is opened by a spring when the operator pushes the lid unit 39 by hand.

According to at least one of the embodiments described above, an energy modulation unit is provided corresponding to the portion of the irradiation port cover closest to the patient, and widens the Bragg peak of the passing particle beam, thereby making it possible to suppress radial widening of the particle beam while widening the Bragg peak of the particle beam.

Furthermore, according to at least one embodiment, by providing a second energy modulation unit that can be moved between a position where it is withdrawn from the orbit and a position on the orbit where it overlaps with the first energy modulation unit and compensates for the widening of the Bragg peak, the work of changing the energy modulation unit can be simplified.

In addition, according to at least one embodiment, an opening is provided in a portion of the irradiation port cover that corresponds to a specific direction, allowing access to the energy modulation unit, thereby improving maintainability.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and spirit of the invention.

1 (1A, 1B, 1C, 1D, 1E, 1F, 1G)...particle beam therapy device, 2...beam generator, 3...circular accelerator, 4...beam transport line, 5...rotating gantry, 6...deflection electromagnet, 7...support roller, 8...drive motor, 9...end ring, 10 (10A, 10B, 10C, 10D, 10E, 10F, 10G)...irradiation port, 11...scanning electromagnet, 12...treatment space, 13...treatment table, 14...building, 15...treatment room, 16...inner wall, 17...support part, 18...reverse rotation synchronous motor, 19...decorative wall, 20a, 20b...track rail, 21...moving floor, 22...high frequency acceleration cavity, 23, 24...deflection electromagnet, 2 5...quadrupole electromagnet, 30...beam emission section, 31 (31A, 31B, 31C, 31D, 31E, 31F, 31G)...irradiation port cover, 32...body cover, 33...frame, 34...dose monitor, 35...position monitor, 36...range shifter, 37...connection section, 38...opening, 39...lid section, 40...operation section, 41 (41E, 41F)...first energy modulation section, 42...second energy modulation section, 43...ridge bar, 44 (44a, 44b)...step section, 45...guide section, 46...moving and holding section, 47...positioning section, 48...latch section, 50...irradiation control system, 51...lid driving section, 52...guide driving section, 53...latch driving section, 5 4...position detection sensor, 55...latch sensor, 56...first tag, 57...second tag, 58...first tag reading unit, 59...second tag reading unit, 60...notification output unit, 61...setting storage unit, 62...placement determination unit, 63...tag determination unit, 64...irradiation control unit, 71...opening, 72...decorative cover, 73...opening, 74...retraction unit, 80...sliced surface, 81...irradiation spot, 82, 83, 84...Bragg peak, 90, 91, 92...Gaussian distribution, 93, 94a, 94b...Bragg peak, 95, 96a, 96b...energy distribution, B(B1, B2)...particle beam, D...vacuum duct, F...scanning range, G1, G2...line of sight direction, J...axis of rotation, K...affected area, M1...vertical dimension of opening, M2...horizontal dimension of opening, N1...area of first energy modulation section, N2...area of second energy modulation section, P...patient, Q1...range in which the affected area is located inside the patient's body, Q2...depth range in which the Bragg peak occurs, R1...width of ridge bar, R2...height of step, R3...width of step, R4...height of ridge bar of first energy modulation section, R5...height of ridge bar of second energy modulation section, R6, R7...height of step, R8, R9...width of step, T1...thickness of first energy modulation section, T2...thickness of first energy modulation section.

Claims (10)

a beam emission unit that emits a particle beam toward a patient;
an irradiation port cover for covering the beam emission portion;
an energy modulation unit provided in a portion of the irradiation port cover closest to the patient and configured to widen a Bragg peak of the particle beam passing through the irradiation port cover;
Equipped with
The irradiation port cover has a U-shape in cross section, and the energy modulation unit is disposed at the bottom thereof .
Particle beam therapy device. The particle beam therapy device according to claim 1, further comprising a position determining unit provided on the irradiation port cover to determine the position of the energy modulation unit. The particle beam therapy device according to claim 2, wherein the position determination unit is a portion of the irradiation port cover that defines a shape in which the energy modulation unit is disposed. The particle beam therapy device according to any one of claims 1 to 3, wherein a plurality of the energy modulation units are arranged in a line along the trajectory of the particle beam, and at least one of the energy modulation units is provided corresponding to a portion of the irradiation port cover that is closest to the patient. A stand is provided to which the irradiation port cover is detachably attached,
5. The particle beam therapy system according to claim 1, wherein the energy modulation unit is connected to the irradiation port cover, and the energy modulation unit is detachably attached to the gantry together with the irradiation port cover. The particle beam therapy device according to any one of claims 1 to 5, wherein the energy modulation section is made of an aluminum ridge filter. The particle beam therapy device according to any one of claims 1 to 5, wherein the energy modulation section is made of a ridge filter made of acrylic. The particle beam therapy device according to any one of claims 1 to 5, wherein the energy modulation section is formed of a porous material. The particle beam therapy device according to claim 8, wherein at least a portion of the irradiation port cover is formed from the porous material, and this portion serves as the energy modulation section. A step of a beam output unit outputting a particle beam;
a step of causing the particle beam to pass through an energy modulation unit provided in a portion of an irradiation port cover covering the beam emission unit that is closest to a patient;
broadening a Bragg peak of the particle beam by the energy modulation unit;
Including,
The irradiation port cover has a U-shape in cross section, and the energy modulation unit is disposed at the bottom thereof .
A method for operating a particle beam therapy device .

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