JP2838006B2 - Radiotherapy equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing radiotherapy, and more particularly to a radiotherapy apparatus capable of performing radiotherapy and positioning of an affected part with the same apparatus.

[0002]

2. Description of the Related Art FIGS. 5 (a) and 5 (b) show the structure near the exit of an acceleration tube of a conventional radiotherapy apparatus. In the drawing, reference numeral 1 denotes an acceleration tube for accelerating a beam;
Is an electromagnet for rotating and deflecting the beam 270 degrees, 4 is a 270 degree rotation orbit of the beam, 5 is a beam extraction window for extracting the beam into the atmosphere, 6 is a target for applying a beam to generate X-rays, and 7 is a target. X generated from target 6
The line 8 indicates the moving direction of the target 6.

A conventional radiation therapy apparatus is configured as described above, and an electron beam accelerated by an acceleration tube 1 is deflected by an electromagnet 3 attached to a vacuum duct 2.
After taking a 270 degree rotation orbit 4, the beam is output to the atmosphere from a beam extraction window 5. The electron beam emitted into the atmosphere collides with the target 6 and generates X-rays 7. In the case of radiation treatment, the treatment is performed by applying the X-rays 7 to the affected part of the patient. On the other hand, in the case of treatment with an electron beam, the target 6 is moved in the direction of arrow 8 to place the target 6 outside the beam line, and the electron beam output from the beam extraction window 5 to the atmosphere is directly applied to the affected part of the patient. The treatment is performed by applying.

[0004]

In the conventional radiotherapy apparatus as described above, a beam of several MeV to 20 MeV is accelerated to perform radiotherapy. However, positioning of an affected part before the therapy is performed is as follows. Since the treatment is performed by another machine (simulator) using a beam of several tens of Kev, there is a problem that the affected part is displaced when the patient moves, so that accurate treatment cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to reduce the size and cost of the apparatus by enabling the same apparatus to perform radiation therapy and positioning of an affected part. An object of the present invention is to provide a radiotherapy apparatus capable of improving the positioning accuracy of an affected part and performing positioning in a short time.

[0006]

A radiotherapy apparatus according to the present invention outputs a high-energy beam for treatment and a low-energy beam for positioning to the atmosphere from a beam extraction window using the same vacuum duct. The low energy beam is made to collide with the target in a short trajectory by the trajectory changing means.

[0007]

According to the radiotherapy apparatus of the present invention, a high-energy beam for treatment and a low-energy beam for positioning are used.
Since the beam is output from the beam extraction window through the same vacuum duct, the affected part can be positioned without moving the patient, and accurate treatment can be performed. Also,
Since the trajectory of the low-energy beam is shortened by the trajectory changing means, a decrease in output due to divergence is reduced, and positioning can be performed in a short time.

[0008]

【Example】

Embodiment 1 FIG. FIG. 1 shows an embodiment of the present invention, in which 1, 2 and 4 to 8 are the same as the above-mentioned conventional apparatus. Reference numeral 9 denotes a low-energy beam for positioning, which is accelerated by the accelerating tube 1 together with a high-energy beam for treatment having a 270-degree rotation orbit 4, and has a low energy beam
ev, and is guided to the same vacuum duct 2 together with the high energy beam. Reference numeral 10 denotes a trajectory changing means for the low-energy beam 9 which is disposed in the vacuum duct 2 so as to be able to advance and retreat. In this embodiment, the X-ray 7 is generated by colliding the low-energy beam 9 and the generated X-ray. A target for directly outputting 7 from the beam extraction window 5 to the atmosphere is used. Reference numeral 11 denotes a bellows for moving the target 10 forward and backward in the vacuum duct 2.

Next, the operation of the first embodiment will be described.
When used as a therapeutic device, as shown in FIG. 1A, the target 10 is retracted by driving the bellows 11, and the target 10 is removed from the 270 degree rotation orbit 4 of the high energy beam. And in this state, several MeV ~
A high energy beam of 20 MeV is guided to the vacuum duct 2. Then, the high-energy beam is 270-degree rotationally deflected by an electromagnet (not shown), takes a 270-degree rotational trajectory 4, and is output from the beam extraction window 5 to the atmosphere. When the electron beam emitted into the atmosphere collides with the target 6, X-rays 7 are generated, and the X-rays 7 are applied to the affected part of the patient to perform radiation therapy. In addition, a treatment with an electron beam is performed by directly irradiating the affected part of the patient with the electron beam emitted into the atmosphere.

On the other hand, when used for positioning, as shown in FIG. 1B, the target 10 is advanced by driving the bellows 11 so that the target 10 is positioned within the beam line of the low energy beam 9. At the same time, the target 6 is moved in the direction of the arrow 8 to remove the target 6 from the beam line. And in this state,
A low energy beam 9 of several tens of Kev is guided from the acceleration tube 1 to the vacuum duct 2. Then, this low energy beam 9
Does not rotate and deflect 270 degrees in the vacuum duct 2,
An X-ray 7 is generated by colliding directly with the target 10 in a short orbit. When the low-energy beam 9 is rotated and deflected 270 degrees like a high-energy beam, the low-energy beam 9 has a strong divergence (a large space charge effect due to a low speed), and the beam current to the target decreases. Although the X-ray intensity generated by the irradiation decreases and positioning takes a long time, the X-ray intensity for positioning is reduced by colliding the low-energy beam 9 with the target 10 in a short trajectory as in the present embodiment. It becomes strong and can be positioned in a short time.

Embodiment 2 FIG. In the first embodiment, the X-rays 7 generated from the target 10 are directly applied to the affected part of the patient to perform positioning. However, since the positions of the positioning target 10 and the treatment target 6 are different, the affected part is The spread state of the passing X-ray 7 is different, and the size of the affected part on the positioning X-ray 7 and the size of the affected part on the therapeutic X-ray 7 are shifted. Therefore, in the present embodiment, as shown in FIG. 2, a collimator 12 having a hole having a diameter of 1 to 2 mm is provided at the end of the treatment target 6. At the time of positioning, the X-rays 7 are generated by the target 10. The X-rays 7 are collimated by the collimator 12, and thereafter, the beam is expanded. For this reason, it becomes equivalent to the case where the X-ray 7 ′ is generated from the collimator 12, and the distance from the affected part becomes the same at the time of positioning and at the time of treatment. For this reason, the size of the affected part does not shift, and more accurate treatment can be performed.

Embodiment 3 FIG. FIG. 3 shows another embodiment in the case where the steering coil 13 is used for positioning.
And deflects the low-energy beam 9 as shown by the arrow 14 so that the low-energy beam 9 is directly output to the atmosphere from the beam extraction window 5 without taking the 270 degree rotation orbit 4. Thereby, the low-energy beam 9 can be applied to the same target 6 as in the treatment at the shortest distance,
The positioning time can be shortened and the size of the affected part can be prevented from shifting at the same time.

Embodiment 4 FIG. FIG. 4 shows still another embodiment when used for positioning. A Q-magnet 15 is disposed at the outer peripheral position of the entrance of the vacuum duct 2 so that the low-energy beam 9 converges and then reaches the target. FIG. 4A shows a case in which the present invention is applied to a device using a positioning target 10 and a collimator 12, and FIG. 4B shows a case in which the present invention is applied to a device using a steering coil 13. Show the case. In this way, by converging the low energy beam 9 with the Q-magnet 15 and then hitting the target 6 or 10, the X-ray intensity can be further increased, and the positioning time can be further shortened.

[0014]

The present invention is configured as described above, and outputs a high-energy beam for treatment and a low-energy beam for positioning from the beam extraction window through the same vacuum duct. The position of the diseased part can be determined without moving the patient, accurate treatment can be performed without displacement of the diseased part, and a compact and inexpensive device can be obtained by using a common vacuum duct. Also,
The low energy beam can collide with the target in a short trajectory by the trajectory changing means, so that a decrease in output due to divergence is reduced and positioning can be performed in a short time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an acceleration tube outlet of a radiotherapy apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of an acceleration tube outlet of a radiotherapy apparatus according to Embodiment 2 of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of an acceleration tube outlet of a radiotherapy apparatus according to Embodiment 3 of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of an acceleration tube outlet of a radiotherapy apparatus according to Embodiment 4 of the present invention.

FIG. 5 is a plan view and a cross-sectional view showing a configuration of an acceleration tube outlet of a conventional radiotherapy apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Accelerator tube 2 Vacuum duct 3 Electromagnet 4 270 degree rotation orbit 5 Beam extraction window 6 Target for treatment 7 X-ray 9 Low energy beam 10 Target for positioning (orbit changing means) 12 Collimator 13 Steering coil (orbit changing means) 15 Q-magnet

Claims (1)

(57) [Claims] An accelerating tube for accelerating a high energy beam for treatment and a low energy beam for positioning, a vacuum duct through which each accelerated beam is guided, and rotating and deflecting the high energy beam attached to the vacuum duct A radiotherapy apparatus comprising: an electromagnet for outputting the beam from the beam extraction window to the atmosphere; and a trajectory changing means provided in the vacuum duct to shorten the trajectory of the low energy beam.