Particle beam treatment device

Abstract

To provide a particle beam treatment device which can reduce the variations in the quality of a particle beam in a treatment in a plurality of irradiation spaces.SOLUTION: A particle beam treatment device 1 comprises a plurality of energy change units 50A, 50B which are provided in a plurality of branch paths 31A, 31B to change the energy of a particle beam. Namely, the individual energy change units 50A, 50B are provided for the irradiation spaces of a plurality of irradiation chambers 101A, 101B. In a case, on the downstream with respect to the energy change units 50A, 50B of the respective branch paths 31A, 31B, a difference in a structure related to adjustment of a transport parameter of the particle beam can be easily reduced. Therefore, adjustment in the transport parameter in each transport path 4 to the irradiation spaces of the plurality of irradiation chambers 101A, 101B becomes easy.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a particle beam therapy system. [Background technology]

[0002] A particle beam therapy system is known, for example, as disclosed in Patent Document 1. The particle beam therapy system includes an accelerator that accelerates particles to generate a particle beam, an irradiation device that irradiates the particle beam generated by the accelerator, and a transport path that transports the particle beam from the accelerator to the irradiation device. In a building where the particle beam therapy system is installed, one irradiation device is provided for each accelerator. Therefore, the transport path extends from the accelerator to one irradiation room. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-163229 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, multiple irradiation devices may be installed in a building. In this case, the transport path extends from the accelerator and branches into multiple branch paths, transporting particle beams to multiple irradiation spaces. In this case, an energy change unit that changes the energy of the particle beam is installed in the common path upstream of the branch point in the transport direction. In such a configuration, it is difficult to adjust the transport parameters of the particle beam downstream of the energy change unit, which leads to a problem that the quality of the particle beam is likely to vary during treatment in multiple irradiation spaces.

[0005] Therefore, an object of the present invention is to provide a particle beam therapy system that can reduce variations in particle beam quality during treatment in multiple irradiation spaces. [Means for solving the problem]

[0006] The particle beam therapy device according to the present invention comprises an accelerator that accelerates particles to generate a particle beam, a transport path that extends from the accelerator and branches into a plurality of branch paths and is capable of transporting the particle beam, and a plurality of energy changing units that are provided in each of the plurality of branch paths and change the energy of the particle beam.

[0007] The particle beam therapy device according to the present invention includes a transport path extending from an accelerator, branching into multiple branch paths, and configured to transport particle beams. Therefore, particle beams generated by the accelerator are irradiated in one of the irradiation spaces via one of the branch paths. In contrast, the particle beam therapy device includes multiple energy change units provided in each of the multiple branch paths to change the energy of the particle beam. That is, individual energy change units can be provided for each of the multiple irradiation spaces. In this case, structural differences related to the adjustment of particle beam transport parameters can be easily reduced downstream of the energy change units of each of the branch paths. Therefore, the adjustment of transport parameters for each transport path for the multiple irradiation spaces is facilitated. As a result, variation in particle beam quality can be reduced during treatment in multiple irradiation spaces.

[0008] The branch paths may have substantially the same structure downstream of the energy change unit in the transport direction of the particle beam. In this case, the configuration related to the adjustment of the transport parameters of the particle beam can be substantially the same downstream of the energy change unit of each branch path. Therefore, the transport parameters of each transport path for the multiple irradiation spaces can be easily adjusted.

[0009] Each branch path may have an irradiation field forming device, downstream of the energy changing unit in the particle beam transport direction, for forming an irradiation field of the particle beam to be irradiated onto the irradiation target. In this case, by reducing the structural difference of the irradiation field forming device in each irradiation space, it becomes easy to adjust the transport parameters of each transport path for the multiple irradiation spaces.

[0010] Each branch path may have an irradiation direction changing device that changes the irradiation direction of the particle beam irradiated onto the irradiation target, downstream of the energy changing unit in the transport direction of the particle beam. In this case, by reducing the structural difference between the irradiation direction changing devices in each irradiation space, it becomes easier to adjust the transport parameters in each transport path for the multiple irradiation spaces.

[0011] The beam irradiation device may further include a selector for selecting the energy of the particle beam, which is provided in each of the plurality of branch paths downstream of the energy changer in the transport direction of the particle beam. In this case, by reducing the difference in the position of the selector in each of the branch paths, it becomes easier to adjust the transport parameters in each of the transport paths for the plurality of irradiation spaces.

[0012] The plurality of branch paths may be provided so as to be capable of transporting the particle beam to a plurality of irradiation spaces where the particle beam is irradiated onto the irradiation target. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a particle beam therapy system that can reduce variations in particle beam quality during treatment in a plurality of irradiation spaces. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a plan view of a particle beam therapy system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic configuration diagram of the vicinity of an irradiation unit of the particle beam therapy system of FIG. [Figure 3] FIG. 1 illustrates layers established for a tumor. [Figure 4] FIG. 10 is a schematic diagram for explaining a base axis of an irradiation unit. [Figure 5] FIG. 1 is a plan view of the particle beam therapy system according to a comparative example. [Figure 6] FIG. 1 is a plan view of the particle beam therapy system according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] A preferred embodiment of a particle beam therapy system according to the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted. In this embodiment, a case will be described in which the particle beam therapy system is a charged particle beam therapy system. A particle beam therapy system is used, for example, in cancer treatment, and is a system that irradiates a tumor (irradiation target) inside a patient's body with particle beams such as proton beams.

[0016] The schematic configuration of a particle beam therapy system according to this embodiment will be described. Fig. 1 is a plan view of the particle beam therapy system according to one embodiment of the present invention. As shown in Fig. 1, the particle beam therapy system 1 includes an accelerator 2 that generates particle beams, a plurality of rotatable irradiation devices 3 that irradiate a patient 15 on a treatment table 16 with particle beams from any direction, and a transport path 4 that transports the particle beams generated by the accelerator 2 to the irradiation devices 3. Each device of the particle beam therapy system 1 is installed, for example, in a room in a building 100.

[0017] In this embodiment, the building 100 has a plurality of irradiation rooms 101 for one accelerator 2. One irradiation device 3 is provided in each irradiation room 101. In the example shown in FIG. 1, two irradiation rooms 101 and two irradiation devices 3 are provided, but the number of irradiation rooms 101 and irradiation devices 3 is not particularly limited. Details of the configuration of the transportation path 4 and the layout of the particle beam therapy device 1 will be described later. The number of irradiation devices 3 provided in one irradiation room 101 does not need to be one, and a plurality of irradiation devices 3 may be provided in one irradiation room 101.

[0018] The irradiation device 3 includes an irradiation field forming device 6 and a gantry 5 (irradiation direction changing device). The irradiation field forming device 6 is a device that forms an irradiation field of particle beams to be irradiated onto the irradiation target. The irradiation field forming device 6 is attached to the gantry 5 that is provided so as to surround the treatment table 16. The irradiation field forming device 6 can be rotated around the treatment table 16 by the gantry 5. The gantry 5 can be rotated around its rotation axis. The transport path 4 enters the gantry 5 from the rear end side. Then, the transport path 4 changes the trajectory of the particle beam to the outer periphery side by a bending electromagnet 7, and then the trajectory of the particle beam is significantly bent by a bending electromagnet 8 (an example of a sextupole magnet or a bending magnet with sextupole components) so that the particle beam enters the irradiation device 3 from the outer periphery side.

[0019] A momentum analyzing slit 55 is provided between the bending electromagnets 7 and 8. The bending electromagnets 7, 55, and 8 function as an analyzer 57 that defines the momentum dispersion (defines the spread of energy). Note that a quadrupole magnet 56 may be provided between the bending electromagnets 7 and 8 in addition to the momentum analyzing slit 55.

[0020] FIG. 2 is a schematic diagram of the vicinity of the irradiation unit of the particle beam therapy device of FIG. 1. In the following explanation, the terms "X-axis direction," "Y-axis direction," and "Z-axis direction" are used. The "X-axis direction" is the direction along the basic axis AX of the irradiation device 3, and is the depth direction of irradiation of the particle beam B. The "basic axis AX" will be described in detail later. FIG. 2 shows the particle beam B being irradiated along the basic axis AX. The "Y-axis direction" is one direction in a plane perpendicular to the X-axis direction. The "Z-axis direction" is the direction perpendicular to the Y-axis direction in a plane perpendicular to the X-axis direction.

[0021] The detailed configuration of the particle beam therapy system 1 according to this embodiment will be described with reference to Figures 1 and 2. An irradiation system using a scanning method is shown as an example of the particle beam therapy system 1, but this is not particularly limited, and a broad beam method or other irradiation methods may be adopted. The scanning method is not particularly limited, and line scanning, raster scanning, spot scanning, etc. may be adopted. The particle beam therapy system 1 includes an accelerator 2, an irradiation system 3, and a transport path 4, as well as a control unit 80 and a treatment planning device 90. One of the multiple irradiation systems 3 is shown in Figure 2.

[0022] The accelerator 2 is a device that accelerates charged particles to generate a particle beam B of a predetermined energy. The particle beam B generated by the accelerator 2 travels along a trajectory formed by a transport path 4 and is guided to the irradiation device 3. Examples of the accelerator 2 include a cyclotron, a synchrocyclotron, and a linac. These are fixed energy accelerators that generate a particle beam B of a fixed energy. A cyclotron that emits a particle beam B of a predetermined energy is used as the accelerator 2 in this embodiment.

[0023] The irradiation device 3 irradiates a particle beam B generated by an accelerator 2. Specifically, as shown in FIG. 2, the irradiation device 3 irradiates a tumor (irradiation target) 14 inside the body of a patient 15 with the particle beam B. Charged particles, which are charged particles accelerated to high speeds, include, for example, a proton beam, a heavy particle (heavy ion) beam, and an electron beam. Specifically, the irradiation device 3 irradiates the tumor 14 with the particle beam B, which is emitted from an accelerator 2 that accelerates charged particles generated by an ion source (not shown) and transported through a transport path 4. The irradiation field forming device 6 of the irradiation device 3 includes a scanning electromagnet 10, a duct 11, a dose monitor 12 (an example of a monitor), a position monitor 13 (an example of a monitor), a collimator 17, and a range shifter 30. The scanning electromagnet 10, the duct 11, the monitors 12 and 13, the collimator 17, and the range shifter 30 are housed in an irradiation nozzle 9, which serves as a housing. In this way, the irradiation nozzle 9 accommodates each of the main components to form the irradiation nozzle 6. In addition to the above-mentioned elements, a sextupole magnet or a bending magnet having sextupole components, and a profile monitor may be provided upstream of the scanning electromagnet 10.

[0024] The scanning electromagnets 10 include a Y-axis scanning electromagnet 10a and a Z-axis scanning electromagnet 10b. Each of the Y-axis scanning electromagnet 10a and the Z-axis scanning electromagnet 10b is composed of a pair of electromagnets, and changes the magnetic field between the pair of electromagnets in response to a current supplied from the control unit 80, thereby scanning the particle beam B passing between the electromagnets. By using the scanning electromagnets 10, the Y-axis scanning electromagnet 10a scans the particle beam B in the Y-axis direction, and the Z-axis scanning electromagnet 10b scans the particle beam B in the Z-axis direction. These scanning electromagnets 10 are arranged in this order on the base axis AX, downstream of the accelerator 2 from the particle beam B. The scanning electromagnets 10 scan the particle beam B so that the particle beam B is irradiated along a scanning path pre-planned by the treatment planning device 90. A single scanning electromagnet may be used to scan the particle beam B in both the X and Y directions.

[0025] The duct 11 is disposed on the base axis AX and downstream of the scanning electromagnet 10. The duct 11 guides the particle beam B scanned by the scanning electromagnet 10 to a dose monitor 12 disposed downstream of the duct 11. The duct 11 has, for example, a truncated cone shape widening from upstream to downstream of the base axis AX. The duct 11 penetrates along the base axis AX. The interior of the duct 11 is exposed to the atmosphere. That is, the duct 11 contains the atmosphere (air) therein. The atmosphere (air) contains, for example, nitrogen and oxygen. For example, the interior of the duct 11 is exposed to the atmosphere. In this case, the entire interior of the irradiation nozzle 9 may be exposed to the atmosphere, or only the interior of the duct 11 may be configured to be exposed to the atmosphere. Note that the above-mentioned portion may not be exposed to the atmosphere, may be filled with helium, or may be evacuated.

[0026] The dose monitor 12 is disposed on the base axis AX and downstream of the duct 11. The position monitor 13 detects and monitors the beam shape and position of the particle beam B. The position monitor 13 is disposed on the base axis AX and downstream of the particle beam B from the dose monitor 12. Each of the monitors 12 and 13 outputs the detected results to the control unit 80.

[0027] The range shifter 30 reduces the energy of the passing particle beam B to shift the range of the particle beam B. In this embodiment, the range shifter 30 is provided at the tip 9a of the irradiation nozzle 9. The tip 9a of the irradiation nozzle 9 is the end portion on the downstream side of the particle beam B.

[0028] The collimator 17 is a member that is provided at least downstream of the scanning electromagnet 10 in the particle beam B, and blocks a part of the particle beam B and allows a part of the particle beam B to pass through. Here, the collimator 17 is provided downstream of the position monitor 13. The collimator 17 is connected to a collimator driver 18 that moves the collimator 17.

[0029] The control unit 80 is configured with, for example, a CPU, a ROM, a RAM, etc. The control unit 80 controls the accelerator 2, the scanning electromagnet 10, and the collimator driving unit 18 based on the detection results output from the monitors 12 and 13.

[0030] Furthermore, the control unit 80 of the particle beam therapy system 1 is connected to a treatment planning device 90 that performs treatment planning for particle beam therapy. Before treatment, the treatment planning device 90 measures the tumor 14 of the patient 15 using a CT scan or the like, and plans the dose distribution at each position on the tumor 14. Specifically, the treatment planning device 90 creates a treatment plan map for the tumor 14. The treatment planning device 90 transmits the created treatment plan map to the control unit 80. The treatment plan map created by the treatment planning device 90 plans the scanning path of the particle beam B.

[0031] When irradiating with particle beam B using the scanning method, the tumor 14 is virtually divided into multiple layers in the X-axis direction, and the particle beam is scanned and irradiated in one layer along a scanning path determined in the treatment plan. After the irradiation of the particle beam B in the one layer is completed, the particle beam B is irradiated in the next adjacent layer.

[0032] When particle beam irradiation is performed using the scanning method, particle beam B is first emitted from accelerator 2. The emitted particle beam B is scanned by the control of scanning electromagnet 10 so as to follow a scanning path determined in the treatment plan. As a result, particle beam B is irradiated while being scanned within an irradiation range in one layer set in the Z-axis direction relative to tumor 14. After irradiation of one layer is completed, particle beam B is irradiated to the next layer. In this way, irradiation field forming device 6 can form an irradiation field in one layer.

[0033] An image of particle beam irradiation by the scanning electromagnet 10 under the control of the control unit 80 will be described with reference to Figures 3(a) and (b). Figure 3 is a diagram showing layers set for a tumor. Figure 3(a) shows an irradiated body virtually sliced ​​into multiple layers in the depth direction, and Figure 3(b) shows a particle beam scanning image in one layer as viewed from the depth direction.

[0034] As shown in FIG. 3(a), the irradiated object is virtually sliced ​​into multiple layers in the irradiation depth direction. In this example, the layers are layer L1, layer L2, ... layer L3, in order from the deepest layer (where the range of particle beam B is longest). n-1 , layer L n , layer L n+1 ,...layer L N-1 , layer L N As shown in Fig. 3(b), the particle beam B traces a beam trajectory along the scanning path TL, and in the case of continuous irradiation (line scanning or raster scanning), the particle beam B scans the layer L. n In the case of spot scanning, the light is continuously irradiated along the scanning path TL of the layer L. n The particle beam B is irradiated onto a plurality of irradiation spots. The particle beam B is irradiated along a scanning path TL1 extending in the Z-axis direction, shifted slightly in the Y-axis direction along a scanning path TL2, and then irradiated along the adjacent scanning path TL1. In this way, the particle beam B emitted from the irradiation device 3 controlled by the control unit 80 moves along the scanning path TL.

[0035] FIG. 4 is a schematic diagram for explaining the base axis of the irradiation unit. Referring to FIG. 4, the "base axis AX" of the irradiation device 3 will be explained. The base axis AX is a virtual reference line that serves as a reference when the irradiation device 3 irradiates the particle beam B. When the treatment planning system 90 creates a scanning pattern during treatment planning, the treatment plan is also based on the base axis AX. For example, when setting the layers shown in FIG. 3(a), each layer is a plane perpendicular to the base axis AX. Furthermore, when setting the amount of movement in the Y-axis direction and the Z-axis direction, the position of the base axis AX is also used as a reference. As shown in FIG. 4(a), the base axis AX is perpendicular to the center line CL of the gantry 5 and passes through the center line CL. The base axis AX passes through the isocenter AC on the center line CL of the gantry 5. As shown in FIG. 4(b), when the gantry 5 is rotated to rotate the irradiation device 3 around the isocenter AC, the base axis AX passes through the isocenter AC on the gantry 5 regardless of the position of the irradiation device 3. The XYZ coordinate system is a relative coordinate system that changes depending on the orientation of the base axis AX. Fig. 4 shows the XYZ coordinate system in a state where the base axis AX extends vertically. Fig. 1 above also shows a state where the base axis AX extends horizontally to show the state of the irradiation device 3. Therefore, Fig. 1 shows the XYZ coordinate system corresponding to this state.

[0036] Next, with reference to FIG. 1, a detailed configuration of the transportation route 4 of the particle beam therapy system 1 according to this embodiment and the layout of the building 100 will be described.

[0037] The building 100 has irradiation chambers 101A and 101B lined up in the X-axis direction. The irradiation chamber 101A is arranged on the positive side of the X-axis direction relative to the irradiation chamber 101B. Irradiation devices 3A and 3B are arranged in the irradiation chambers 101A and 101B, respectively. At this time, the irradiation devices 3A and 3B are arranged so that the rotation axis of the gantry 5 is parallel to the Y-axis direction. Furthermore, the front side of the gantry 5 is on the positive side of the Y-axis direction, and the back side of the gantry 5 is on the negative side of the Y-axis direction. The building 100 also has an accelerator room 102 adjacent to the irradiation chambers 101A and 101B on the negative side of the Y-axis direction.

[0038] The irradiation chambers 101A and 101B and the accelerator chamber 102 are provided with a wall 103 extending in the X-axis direction. A wall 104 extending in the Y-axis direction is provided on the positive side of the irradiation chamber 101A in the X-axis direction. A wall 106 extending in the Y-axis direction is provided on the negative side of the irradiation chamber 101A in the X-axis direction. The wall 106 is a partition between the irradiation chambers 101A and 101B. A wall 107 extending in the X-axis direction is provided on the positive side of the irradiation chamber 101A in the Y-axis direction. A wall 108 extending in the Y-axis direction is provided on the negative side of the irradiation chamber 101B in the X-axis direction. A wall 109 extending in the X-axis direction is provided on the positive side of the irradiation chamber 101B in the Y-axis direction. A wall 111 extending in the Y-axis direction is provided on the positive side of the accelerator chamber 102 in the X-axis direction. Wall portion 111 is provided so as to be continuous with wall portion 104. Wall portion 112 extending in the Y-axis direction is provided on the negative side in the X-axis direction of accelerator chamber 102. Wall portion 113 extending in the X-axis direction is provided on the negative side in the Y-axis direction of accelerator chamber 102A.

[0039] An entrance 121 of irradiation chamber 101A is formed between wall 104 and wall 107. An entrance 122 of irradiation chamber 101B is formed between wall 106 and wall 109. Each wall of building 100 functions as a shielding wall that blocks radiation.

[0040] The transport path 4 extends from the accelerator 2 and is configured to be able to transport the particle beam. The transport path 4 extends from the accelerator 2 and branches into multiple branch paths 31A, 31B to transport the particle beam to multiple irradiation chambers 101A, 101B that irradiate the particle beam onto an irradiation target. The transport path 4 has a common path 32 that extends from the accelerator 2 in the X-axis direction. The branch paths 31A, 31B branch from the common path 32 at branch points. The multiple branch paths 31A, 31B are configured to be able to transport the particle beam to multiple irradiation spaces where the particle beam is irradiated onto an irradiation target.

[0041] The branch path 31A extends in the X-axis direction so as to be continuous with the common path 32. The branch path 31A bends toward the positive side in the Y-axis direction at a position on the back surface of the gantry 5 in the X-axis direction. The branch path 31A enters the irradiation device 3A from the back surface of the gantry 5 via a wall 103. Within the irradiation device 3A, the branch path 31A extends obliquely toward the bending electromagnet 8 at the position of the bending electromagnet 7. Inside the bending electromagnet 8, the branch path 31A curves in the same manner as the bending electromagnet 8 and extends to the irradiation port on the downstream side of the irradiation field forming device 6. The branch path 31B bends toward the positive side in the Y-axis direction at a branch point of the common path 32. The branch path 31B enters the irradiation device 3B from the back surface of the gantry 5 via a wall 103. The configuration of the branch path 31B within the irradiation device 3B is the same as that of the branch path 31A. In the following description, the terms "upstream side" and "downstream side" are used based on the transport direction of the particle beam.

[0042] In the accelerator chamber 102, a bending magnet 41A, a quadrupole magnet 42A, a bending magnet 43A, a quadrupole magnet 44A, and a quadrupole magnet 46A are provided in this order from upstream to downstream near the bend in the branch path 31A. The bending magnets 41A and 43A are electromagnets for bending the trajectory of the particle beam. The quadrupole magnets 42A, 44A, and 46A are magnets for converging the particle beam and shaping the particle beam. Similar to the branch path 31A, a bending magnet 41B, a quadrupole magnet 42B, a bending magnet 43B, a quadrupole magnet 44B, and a quadrupole magnet 46B are provided in this order from upstream to downstream near the bend in the branch path 31B. A plurality of quadrupole magnets 47 are provided in the linear portion of the branch path 31A upstream of the bending magnet 41A. A profile monitor and a beam stopper (not shown) may be provided between the plurality of quadrupole magnets 47. These magnets may be electromagnets.

[0043] The particle beam therapy system 1 includes a plurality of energy conversion units 50A, 50B provided in each of the plurality of branch paths 31A, 31B to change the energy of the particle beam. The energy conversion units 50A, 50B are provided in the branch paths 31A, 31B downstream of the quadrupole magnet 46A and spaced apart from the wall 103 toward the negative side in the Y-axis direction. The energy conversion units 50A, 50B are configured, for example, by degraders 51A, 51B equipped with attenuation members that attenuate the energy of the particle beams that have passed through them. The degraders 51A, 51B can adjust the attenuation of the energy by adjusting the thickness of the attenuation members. Furthermore, the energy conversion units 50A, 50B may further include collimators 52A, 52B downstream of the degraders 51A, 51B. The collimators 52A and 52B regulate the emittance (the spread and directional variation of the beam position) of the beam expanded by the degrader, and are made of, for example, a hollow metal material and have a hollow or slit shape. The collimators 52A and 52B can be provided downstream of the degraders 51A and 51B and spaced from the wall 103 on the negative side in the Y direction.

[0044] The energy changers 50A and 50B, the bending electromagnet 7, the quadrupole magnet 56, the momentum analysis slit 55, and the bending electromagnet 8 constitute a selection system (ESS: Energy Selection System) that selects the energy of a particle beam. In this way, an individual selection system is provided for each branch path 31A and 31B. That is, an individual selection system is provided for each irradiation device 3A and 3B. The selection system for the irradiation device 3A and the selection system for the irradiation device 3B are arranged so that the relative positions of the components that make up each selection system are the same and have the same structure. In this embodiment, the selection system is composed of the energy changers 50A and 50B, the bending electromagnet 7, the quadrupole magnet 56, the momentum analysis slit 55, and the bending electromagnet 8, but the selection system that selects the energy of a particle beam only needs to have at least the energy changers 50A and 50B.

[0045] The branch paths 31A, 31B have substantially the same structure downstream of the energy changing units 50A, 50B. Specifically, the irradiation nozzle 6 and gantry 5 downstream of the energy changing unit 50A in the branch path 31A and the irradiation nozzle 6 and gantry 5 downstream of the energy changing unit 50B in the branch path 31B have the same structure. That is, the irradiation nozzle 6 of the irradiation device 3A and the irradiation nozzle 6 of the irradiation device 3B have similar components arranged in a similar manner. The gantry 5 of the irradiation device 3A and the gantry 5 of the irradiation device 3B have similar components arranged in a similar manner.

[0046] Next, the actions and effects of the particle beam therapy system 1 according to this embodiment will be described.

[0047] First, a particle beam therapy system 201 according to a comparative example shown in Fig. 5 will be described. The particle beam therapy system 201 according to the comparative example includes an accelerator 2 in an accelerator room 202 in a building 200, an irradiation device 3 that irradiates particle beams generated by the accelerator 2, and a transport path 204 that transports the particle beams from the accelerator 2 to the irradiation device 3. The building 200 in which the particle beam therapy system 201 is installed has one irradiation device 3 for each accelerator 2. Therefore, the transport path 204 extends from the accelerator 2 to one irradiation room 203. In this particle beam therapy system 201, the accelerator 2, the selection system 250, the transport path 204, and the irradiation device 3 are linearly arranged. Therefore, this structure cannot be expanded to a particle beam therapy system in which irradiation devices are arranged in multiple irradiation rooms.

[0048] Next, a particle beam therapy system 301 according to a comparative example shown in FIG. 6 will be described. This particle beam therapy system 301 includes multiple irradiation chambers 301A and 301B and irradiation devices 3A and 3B. A transport path 304 extends from an accelerator 2 and branches into multiple branch paths 331A and 331B, transporting particle beams to the multiple irradiation chambers 301A and 301B. In this case, a selection system 350 including an energy changer 351 that changes the energy of the particle beam is provided in a common path 330 upstream of the branch point of the transport path 304 in the transport direction. In this configuration, it is difficult to adjust the transport parameters of the particle beam downstream of the energy changer 351. A problem arises in that the quality of the particle beam is likely to vary during treatment between the multiple irradiation chambers 301A and 301B.

[0049] For example, the branch path 331B for the irradiation chamber 301B is longer than the branch path 331A for the irradiation chamber 301A. Therefore, in the branch path 331B, the particle beam tends to spread downstream of the energy changing unit 351. Therefore, a larger number of electromagnets and the like are provided downstream of the energy changing unit 351 in the transport path 304 for the irradiation chamber 301B than in the transport path 304 for the irradiation chamber 301A. Therefore, in order to distribute the particle beams to each of the irradiation chambers 301A and 301B, the particle beam therapy device 301 requires transport parameters for each energy in the transport path, but such adjustment is difficult. Here, using a large electromagnet to facilitate adjustment increases costs. Therefore, using a small electromagnet to reduce costs results in variations in the quality of the therapeutic beam in each irradiation space.

[0050] In addition, to shorten the treatment time, it is necessary to widen the momentum dispersion in order to make the Bragg peak thicker. However, in the particle beam therapy system 301 according to the comparative example, the selection system 350 needs to be installed far away from the irradiation devices 3A and 3B, which makes it difficult to shorten the treatment time.

[0051] In contrast, the particle beam therapy system 1 according to this embodiment includes a transport path 4 extending from an accelerator 2, branching into multiple branch paths 31A and 31B, and transporting particle beams to multiple irradiation chambers 101A and 101B where the particle beams are irradiated onto the irradiation target. Therefore, particle beams generated by the accelerator 2 are irradiated in one of the irradiation chambers 101A and 101B via one of the branch paths 31A and 31B of the transport path 4. In contrast, the particle beam therapy system 1 includes multiple energy changers 50A and 50B provided in each of the multiple branch paths 31A and 31B, respectively, for changing the energy of the particle beams. That is, individual energy changers 50A and 50B can be provided for each of the multiple irradiation chambers 101A and 101B. In this case, structural differences related to the adjustment of particle beam transport parameters can be easily reduced downstream of the energy changers 50A and 50B of each branch path 31A and 31B. This makes it easy to adjust the transport parameters for the plurality of irradiation chambers 101A and 101B in each transport route 4. As described above, it is possible to reduce variations in the quality of particle beams in treatments in the irradiation spaces of the plurality of irradiation chambers 101A and 101B.

[0052] The branch paths 31A and 31B may have substantially the same structure downstream of the energy changing units 50A and 50B in the transport direction of the particle beam. In this case, the branch paths 31A and 31B can have substantially the same configuration for adjusting the transport parameters of the particle beam downstream of the energy changing units 50A and 50B. This facilitates the adjustment of the transport parameters of each transport path 4 for the irradiation spaces of the multiple irradiation chambers 101A and 101B.

[0053] Each of the branch paths 31A, 31B may have an irradiation field forming device 6 that forms an irradiation field of the particle beam to be irradiated to the irradiation target, downstream of the energy changing units 50A, 50B in the transport direction of the particle beam. In this case, by reducing the structural difference of the irradiation field forming device 6 in the irradiation space of each irradiation chamber 101A, 101B, it becomes easy to adjust the transport parameters of each transport path 4 for the irradiation space of the multiple irradiation chambers 101A, 101B.

[0054] Each of the branch paths 31A and 31B may have a gantry 5 (irradiation direction changing device) that changes the irradiation direction of the particle beam irradiated onto the irradiation target, downstream of the energy changing units 50A and 50B in the particle beam transportation direction. In this case, by reducing the structural difference of the gantry 5 in each irradiation chamber, it becomes easy to adjust the transport parameters of each transport path 4 for the irradiation spaces of the multiple irradiation chambers 101A and 101B.

[0055] A selector 57 for selecting the energy of the particle beam may be provided in each of the plurality of branch paths 31A, 31B downstream of the energy changer 50A, 50B in the transport direction of the particle beam. In this case, by reducing the difference in the position of the selector 57 in each of the branch paths 31A, 31B, it becomes easier to adjust the transport parameters in each transport path 4 for the irradiation spaces of the plurality of irradiation chambers 101A, 101B.

[0056] For example, the transport parameters and position parameters of the gantry 5 employed in the particle beam therapy system 201 used in the comparative example shown in Fig. 5 cannot be directly used for the irradiation systems 3A and 3B shown in Fig. 6. Therefore, it takes time to adjust the transport parameters and position parameters. Furthermore, since the characteristics of the particle beam at the isocenter in the irradiation systems 3A and 3B are different from those in the particle beam therapy system 201, it is not possible to transfer a patient being treated with the particle beam therapy system 201 of Fig. 5 to the particle beam therapy system 301 of Fig. 6 midway (due to equipment maintenance, etc.), or vice versa.

[0057] In contrast, in each of the irradiation devices 3A and 3B of the particle beam therapy system 1 according to this embodiment, the structure downstream of the energy changing units 50A and 50B can be made substantially the same as that of the particle beam therapy system 201 of Fig. 5. Therefore, in each of the irradiation devices 3A and 3B of the particle beam therapy system 1, the transport parameters and the position parameters of the gantry 5 employed in the particle beam therapy system 201 of Fig. 5 can be used.

[0058] Furthermore, providing individual energy conversion units 50A, 50B for the irradiation spaces of the plurality of irradiation chambers 101A, 101B improves the degree of freedom in arranging the accelerator 2 and the transport path 4. Therefore, as shown in Fig. 1, it is possible to adopt a layout that improves the shielding performance against radiation in each room while making the area of ​​the entire building 100 compact.

[0059] The present invention is not limited to the above-described embodiments.

[0060] For example, the specific configuration of the irradiation nozzle is not limited to the above-described embodiment. Furthermore, the irradiation method of the irradiation nozzle is not limited to the above-described scanning method, and may be a broad beam method such as a wobbler method or a double scatterer method.

[0061] Furthermore, the specific configuration of the irradiation direction change device is not limited to the above-described embodiment. For example, a non-rotating device may be used as the irradiation direction change device instead of the rotating device.

[0062] The structure of the building 100 and the layout of each component may be changed as appropriate without departing from the spirit of the present invention.

[0063] For example, the method of branching the transport path is not particularly limited, and a pattern in which a set of bending magnets distributes the particle beam to multiple irradiation chambers may be adopted. For example, in the configuration shown in Figure 1, a branch path extending downward from bending magnet 41B may exist, resulting in a configuration in which the beam is branched into three branch paths. [Explanation of symbols]

[0064] 1...particle beam therapy device, 2...accelerator, 4...transport path, 5...gantry (irradiation direction change device), 6...irradiation field forming device, 31A, 31B...branch path, 32...common path, 50A, 50B...energy change unit, 57...selection unit, 101A, 101B...irradiation room.

Claims

1. an accelerator that accelerates particles to generate a particle beam; a transport path extending from the accelerator and branching into a plurality of branch paths, the transport path being configured to be capable of transporting the particle beam; a plurality of energy changing units provided in the plurality of branch paths, respectively, for changing the energy of the particle beam.

2. The particle beam therapy system according to claim 1 , wherein the branch paths have substantially the same structure downstream of the energy changing unit in the transport direction of the particle beam.

3. 3. The particle beam therapy device according to claim 1, wherein each of the branch paths has an irradiation field forming device, downstream of the energy changing unit in a transport direction of the particle beam, that forms an irradiation field of the particle beam to be irradiated onto an irradiation target.

4. 4. The particle beam therapy device according to claim 1, wherein each of the branch paths has an irradiation direction changing device that changes the irradiation direction of the particle beam irradiated to an irradiation target, downstream of the energy changing unit in the transport direction of the particle beam.

5. 5. The particle beam therapy device according to claim 1, further comprising a selection unit provided in each of the plurality of branch paths, the selection unit selecting an energy of the particle beam downstream of the energy changing unit in the transport direction of the particle beam.

6. 6. The particle beam therapy device according to claim 1, wherein the plurality of branch paths are provided so as to be capable of transporting the particle beam to a plurality of irradiation spaces where the particle beam is irradiated onto an irradiation target.

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