Particle beam therapy apparatus, deflection magnet apparatus, and particle beam adjustment method

Abstract

The invention provides a particle beam treatment device, a deflection magnet device, and a particle beam adjustment method which can effectively obtain deflection force without depending on the deflection direction of a particle beam (B). According to the particle beam therapy device (1), a deflection magnet (45) that deflects a particle beam (B) of a transport unit (20) can rotate around a beam axis (CL) of the particle beam (B). In this case, the deflection magnet (45) can be rotated about the beam axis (CL) in accordance with the direction of deflection of the desired particle beam (B). Therefore, the direction in which the deflection force of the deflection magnet (45) is effectively obtained can be made to coincide with the desired deflection direction of the particle beam (B). According to the above situation, deflection force can be effectively obtained without depending on the deflection direction of the particle beam (B).

Description

Technical Field

[0001] The present invention relates to a particle beam treatment apparatus, a deflection magnet apparatus, and a particle beam adjustment method. Background Art

[0002] Previously, as a particle beam treatment apparatus for treating a diseased part of a patient by irradiating a particle beam, for example, an apparatus described in Patent Document 1 has been known. In the particle beam treatment apparatus described in Patent Document 1, a particle beam is irradiated from an irradiation unit.

[0003] [Prior Art Documents]

[0004] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-209372 Summary of the Invention

[0006] [Problems to be Solved by the Invention]

[0007] Here, the particle beam treatment apparatus has a transport unit that transports a particle beam from an accelerator toward an irradiation unit. A deflection magnet apparatus that deflects the particle beam is provided with respect to such a transport unit. Here, the deflection magnet apparatus sometimes has a deflection magnet adjusted in the X-axis direction and a deflection magnet adjusted in the Y-axis direction. By overlapping the deflection forces generated by such a biaxial deflection magnet, the particle beam is deflected in a desired direction for adjustment. However, in the conventional particle beam treatment apparatus, depending on the deflection angle, the deflection force involved in the overlap sometimes becomes small. Therefore, an effective deflection force sometimes cannot be obtained according to the angle.

[0008] Therefore, an object of the present invention is to provide a particle beam treatment apparatus, a deflection magnet apparatus, and a particle beam adjustment method capable of effectively obtaining a deflection force regardless of the deflection direction of the particle beam.

[0009] [Means for Solving the Problems]

[0010] A particle beam treatment apparatus according to an aspect of the present invention includes: an irradiation unit that irradiates a particle beam to an irradiated object; a transport unit that transports the particle beam; and a deflection magnet apparatus that has a deflection magnet that deflects the particle beam of the transport unit, and the deflection magnet is capable of rotating around the optical axis of the particle beam.

[0011] According to the particle beam treatment apparatus, the deflection magnet that deflects the particle beam of the transport unit is capable of rotating around the optical axis of the particle beam. In such a case, the deflection magnet can be rotated around the optical axis in accordance with the desired deflection direction of the particle beam. Therefore, the direction in which the deflection force of the deflection magnet is effectively obtained can be made to coincide with the desired deflection direction of the particle beam. Based on the above, a deflection force can be effectively obtained regardless of the deflection direction of the particle beam.

[0012] It may be that: the deflection magnet device has a pair of deflection magnets, and the pair of deflection magnets can rotate around the optical axis of the particle beam while being fixed to each other in the rotation direction. When the deflection forces of the pair of deflection magnets coincide, an angle ensuring a large deflection force involved in the coincidence and an angle with a smaller deflection force are formed. By rotating the pair of deflection magnets around the optical axis of the particle beam, the direction ensuring a large deflection force can be made to coincide with the desired deflection direction of the particle beam. Therefore, regardless of the deflection direction of the particle beam around the optical axis, a large deflection force of the pair of deflection magnets can be ensured. Here, since the pair of deflection magnets are in a state of being fixed to each other in the rotation direction, the adjustment of the rotation angle can be easily performed as compared with the case of individually adjusting the rotation angles of the pair of deflection magnets.

[0013] It may be that: the deflection magnet device has a pair of deflection magnets, and one of the pair of deflection magnets can rotate around the optical axis of the particle beam independently of the other. When the deflection forces of the pair of deflection magnets coincide, an angle ensuring a large deflection force involved in the coincidence and an angle with a smaller deflection force are formed. By rotating the pair of deflection magnets around the optical axis of the particle beam, the direction ensuring a large deflection force can be made to coincide with the desired deflection direction of the particle beam. Therefore, regardless of the deflection direction of the particle beam around the optical axis, a large deflection force of the pair of deflection magnets can be ensured. Here, there are directional components such as the deflection forces of the two canceling each other out when the deflection force of one of the deflection magnets coincides with that of the other. In contrast, one of the pair of deflection magnets can rotate around the optical axis of the particle beam independently of the other. Therefore, the relative rotation angles of the mutually opposing deflection magnets can be adjusted to reduce the directional components that cancel each other out. Thereby, the energy of the deflection magnet device can be effectively utilized.

[0014] It may be that: the deflection magnet device has a single deflection magnet, and the single deflection magnet can rotate around the optical axis of the particle beam. In such a case, the number of magnets of the deflection magnet device can be reduced.

[0015] It may be that: the particle beam treatment device includes an adjustment mechanism that adjusts the rotation angle of the deflection magnet relative to the optical axis. In such a case, by using the adjustment mechanism, the rotation angle of the deflection magnet can be easily and accurately adjusted.

[0016] It may be that: the adjustment mechanism includes a drive unit that rotates the deflection magnet relative to the optical axis. In such a case, the rotation angle of the deflection magnet can be adjusted without relying on manual work by an operator.

[0017] The optical axis extends in the horizontal direction, and the orientation of the magnetic field of the deflection magnet is inclined with respect to the vertical direction.

[0018] It may be that: The particle beam treatment apparatus further includes a control unit that controls the deflection magnet device, and the control unit adjusts the particle beam by rotating the deflection magnet. In this case, the control unit can roughly adjust the direction of the deflection force by rotating the deflection magnet itself.

[0019] It may be that: The control unit performs a second adjustment of the particle beam by electrically controlling the deflection magnet. In this case, the control unit can finely adjust the direction of the deflection force.

[0020] It may be that: The deflection magnet device has a pair of deflection magnets. In the first adjustment, the control unit rotates each deflection magnet relative to the other. In this case, the control unit can also adjust the angle between the pair of deflection magnets through the first adjustment.

[0021] The deflection magnet device according to one aspect of the present invention includes a deflection magnet that deflects a particle beam. In the deflection magnet device, the deflection magnet can rotate about the beam axis of the particle beam.

[0022] According to the deflection magnet device, by being provided at the position where the particle beam passes, the particle beam can be deflected in a desired direction. At this time, the deflection magnet can be rotated about the beam axis in accordance with the desired deflection direction of the particle beam. Therefore, the direction of the deflection force effectively obtained by the deflection magnet can be made to coincide with the desired deflection direction of the particle beam. Based on the above, the deflection force can be effectively obtained regardless of the deflection direction of the particle beam.

[0023] In the particle beam adjustment method according to one aspect of the present invention, the deflection magnet that deflects the particle beam of the transport unit is adjusted. In the particle beam adjustment method, the particle beam is adjusted by rotating the deflection magnet about the beam axis of the particle beam.

[0024] According to the particle beam adjustment method, by providing a deflection magnet at the position where the particle beam passes, the particle beam can be deflected in a desired direction. At this time, the deflection magnet is rotated about the beam axis in accordance with the desired deflection direction of the particle beam. Therefore, the direction of the deflection force effectively obtained by the deflection magnet can be made to coincide with the desired deflection direction of the particle beam. Based on the above, the deflection force can be effectively obtained regardless of the deflection direction of the particle beam.

[0025] [Effects of the Invention]

[0026] According to the present invention, there can be provided a particle beam treatment apparatus, a deflection magnet device, and a particle beam adjustment method that can effectively obtain a deflection force regardless of the deflection direction of the particle beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1It is a schematic structural diagram of a particle beam therapy device showing an embodiment of the present invention.

[0028] Figure 2 It is a schematic side view of a deflection magnet device.

[0029] Figure 3 (a) to Figure 3 (c) is a schematic diagram showing the deflection magnet device.

[0030] Figure 4 (a) to Figure 4 (c) is a schematic diagram showing the deflection magnet device.

[0031] Figure 5 (a) to Figure 5 (c) is a schematic diagram showing the deflection magnet device.

[0032] Figure 6 (a), Figure 6 (b) is a schematic diagram showing the deflection magnet device.

[0033] Figure 7 (a), Figure 7 (b) is a schematic diagram showing an example of an adjustment mechanism.

[0034] Figure 8 (a), Figure 8 (b) is a schematic diagram showing an example of an adjustment mechanism.

[0035] Figure 9 (a), Figure 9 (b) is a schematic diagram showing an example of an adjustment mechanism.

[0036] [Description of symbols]

[0037] 1: Particle beam therapy device

[0038] 2: Irradiation unit

[0039] 3: Accelerator

[0040] 6: Treatment table

[0041] 7: Control unit

[0042] 15: Patient

[0043] 17: Gantry

[0044] 20A: BTS system

[0045] 20B: ESS system

[0046] 20C: GTS system

[0047] 21: Beam pipe

[0048] 30, 30A, 30B, 30C: Deflection magnet device

[0049] 31: Converging electromagnet

[0050] 32: Energy reducer

[0051] 40, 41, 42, 45, 45A, 45B, 45C: Deflection magnet

[0052] 45a: Lower surface

[0053] 46: Magnetic pole

[0054] 47: Coil

[0055] 48: Main body part

[0056] 49: Protruding part

[0057] 50: Adjusting mechanism

[0058] 51A: Supporting part

[0059] 51a: Placing part

[0060] 51B: Supporting part

[0061] 52: Base member

[0062] 53A, 53B: Spacer

[0063] 54: Pin

[0064] 56: Receiving part

[0065] 56a: Receiving hole

[0066] 57: Engaging member

[0067] 57a: Engaging part

[0068] 58: Supporting member

[0069] 60: Driving part (gear)

[0070] 61: Gear

[0071] 62: Rotating shaft

[0072] 63: Pinion

[0073] 64: Driving mechanism

[0074] 65: Driving part

[0075] AE: Adjustment range

[0076] B: Particle beam

[0077] Ba, Bb: Magnetic field

[0078] CL: Beam axis

[0079] Fa, Fb, Fc: Deflection force

[0080] Floss: Component

[0081] Ft: Resultant deflection force

[0082] Fmax: Maximum deflection force

[0083] RDa, RDb: Rotation direction

[0084] θ1: Angle

[0085] θ2, θ3, θ4: Rotation angle Detailed implementation mode

[0086] Hereinafter, a particle beam therapy apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in the description of the drawings, the same reference numerals are assigned to the same elements and repeated descriptions are omitted.

[0087] Figure 1 FIG. is a schematic structural diagram of a particle beam therapy apparatus 1 according to an embodiment of the present invention. The particle beam therapy apparatus 1 is a system used in cancer treatment and the like using radiation therapy. The particle beam therapy apparatus 1 can be an irradiation apparatus related to a scanning method. In addition, the scanning method is not particularly limited, and line scanning, raster scanning, point scanning, etc. can be adopted. The particle beam therapy apparatus 1 includes: an accelerator 3 that accelerates charged particles generated by an ion source device and emits them as a particle beam; an irradiation unit 2 that irradiates a patient 15 with the particle beam; and a transport unit 20 that transports the particle beam emitted from the accelerator 3 to the irradiation unit 2. The irradiation unit 2 is mounted on a gantry 17 provided so as to surround a treatment table 6. The irradiation unit 2 can rotate around the treatment table 6 on which the patient 15 is arranged with the central axis as the rotation center by the gantry 17.

[0088] The accelerator 3 is a device that accelerates charged particles and emits a particle beam B having a preset energy. As the accelerator 3, for example, a cyclotron, a synchrocyclotron, etc. can be cited. The particle beam B generated by the accelerator 3 is transported to the irradiation unit 2 through the transport unit 20. The transport unit 20 connects the accelerator 3 and the irradiation unit 2 and transports the particle beam B emitted from the accelerator 3 to the irradiation unit 2. The detailed structure of the transport unit 20 will be described later.

[0089] The irradiation unit 2 irradiates a particle beam onto a tumor in the patient 15. A particle beam is a substance formed by accelerating charged particles at high speed. Examples thereof include a proton beam, a heavy particle (heavy ion) beam, an electron beam, etc. Specifically, the irradiation unit 2 is a device that irradiates a particle beam onto a tumor, and the particle beam is emitted from an accelerator 3 that accelerates charged particles generated by an ion source (not shown) and is transported by a transport unit 20. The irradiation unit 2 includes a scanning electromagnet. In addition to this, the irradiation unit 2 may include a quadrupole electromagnet, a monitor, a degrader, etc. The scanning electromagnet changes the magnetic field between a pair of electromagnets according to the current supplied from the control unit, so as to scan the particle beam passing between the electromagnets. In addition, the scanning electromagnet scans the particle beam B in such a manner that the particle beam is irradiated according to the scanning pattern pre-planned in the treatment planning device.

[0090] The control unit 7 (refer to Figure 2 ) includes, for example, a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM), etc. The control unit 7 controls the accelerator 3, the transport unit 20, the irradiation unit 2, etc. based on the detection results output from each monitor.

[0091] In addition, the control unit 7 of the particle beam treatment device 1 is connected to a treatment planning device that performs a treatment plan for particle beam treatment. The treatment planning device measures the tumor of the patient 15 using computed tomography (CT), etc. before treatment, and plans the dose distribution (the dose distribution of the particle beam to be irradiated) at each position of the tumor. Specifically, the treatment planning device creates a scanning pattern for the tumor. The treatment planning device sends the created scanning pattern to the control unit 7. In the scanning pattern created by the treatment planning device, it is planned how the particle beam depicts what kind of scanning path at what scanning speed.

[0092] In the case of irradiating a particle beam by the scanning method, the tumor is virtually divided into a plurality of layers, and in one layer, the particle beam is scanned and irradiated in accordance with the scanning path determined in the treatment plan. Then, after the irradiation of the particle beam in the said one layer is completed, the irradiation of the particle beam in the adjacent next layer is performed.

[0093] The transport unit 20 has a beam pipe 21 (transport unit) for transporting the particle beam B and a plurality of electromagnets. The transport unit 20 includes a Beam Transport System (BTS) system 20A, an Energy Selection System (ESS) system 20B, and a Gantry Transport System (GTS) system 20C. The BTS system 20A is a system for transporting the particle beam B. The ESS system 20B is a system for selecting the energy of the particle beam B. The GTS system 20C is a transport system for the particle beam B in the rotating gantry 17. The transport unit 20 includes a deflection magnet device 30 in each system.

[0094] The structural elements in each system will be described. Among them, Figure 1 The structural elements shown are only examples and can be appropriately changed. The BTS system 20A mainly includes a deflection magnet device 30A, a focusing electromagnet 31, and a focusing electromagnet 31. The deflection magnet device 30A has a deflection magnet 40. The deflection magnet 40 is an electromagnet that deflects the particle beam transported by the beam pipe 21. In the present embodiment, the deflection magnet device 30A includes a pair of deflection magnets 40 and can adjust the particle beam using two axes. Among them, as will be described later, the deflection magnet device 30A may also have one deflection magnet 40. The focusing electromagnet 31 is an electromagnet that focuses the particle beam.

[0095] The ESS system 20B includes an energy degrader 32 and a collimator device 33. The energy degrader 32 reduces the energy of the passing particle beam B to adjust the range of the particle beam B. The collimator device 33 is a member for collimating the particle beam.

[0096] The GTS system 20C includes a focusing electromagnet 31, a deflection magnet device 30B, a focusing electromagnet 31, and a deflection magnet device 30C. The deflection magnet device 30B includes a deflection magnet 41 that bends the particle beam B passing through the ESS system 20B toward the outer peripheral side of the rotating gantry 17. The deflection magnet device 30C includes a deflection magnet 42 that bends from the outer peripheral side of the rotating gantry 17 toward the irradiation part 2 on the inner peripheral side.

[0097] Here, the deflection magnet 41 and the deflection magnet 42 are electromagnets for bending the particle beam B to an extent that requires changing the angle of the beam pipe 21. The deflection magnet 41 and the deflection magnet 42 can bend the particle beam B into a desired angle. On the other hand, the deflection magnet 40 deflects and adjusts the particle beam B within the range where the angle of the beam pipe 21 can be maintained. There is no particular limitation, but the deflection angle range of the deflection magnet 40 may be 45° or less, or 90° or less.

[0098] Next, refer to Figure 2 andFigure 3 of (a) to Figure 3 Figures (c) of Figure 3 illustrate the detailed structure of the deflection magnet device 30. In the following description, the direction in which the particle beam B travels is defined as the Z-axis direction. The direction orthogonal to the Z-axis direction is defined as the X-axis direction, and the direction orthogonal to the Z-axis direction and the X-axis direction is defined as the Y-axis direction. The central axis of the beam pipe is defined as the beam axis CL of the particle beam B. Figure 2 is a schematic view of the deflection magnet device 30 observed from the X-axis direction. Figure 2 The deflection magnet device 30 shown in Figure 2 includes a deflection magnet 45A and a deflection magnet 45B. Figure 3 Figure (a) of Figure 3 is a view of the deflection magnet 45A observed from the Z-axis direction. Figure 3 Figure (b) of Figure 3 is a view of the deflection magnet 45B observed from the Z-axis direction. Figure 3 Figure (c) of Figure 3 is a view for explaining the deflection force generated by the deflection magnet 45A and the deflection force generated by the deflection magnet 45B. In addition, Figure 3 of (a) to Figure 3 The deflection magnets 45A and 45B shown in Figures (c) of Figure 3 are set to the "reference posture". In addition, the direction of the deflection force F caused by the deflection action of the deflection magnets 45A and 45B is defined by the direction of the Lorentz force determined by the direction of the magnetic field in the beam axis CL and the direction of the particle beam B. Here, it is assumed that the particle beam B travels on the beam axis CL.

[0099] As Figure 3 shown in Figure (a) of Figure 3 , Figure 3 Figure (b) of Figure 3 , the deflection magnets 45A and 45B include magnetic poles 46 and coils 47. The magnetic poles 46 include a rectangular ring-shaped main body portion 48 surrounding the beam axis CL and a pair of protruding portions 49. The main body portion 48 is arranged such that its central axis coincides with the beam axis CL. As Figure 3 shown in Figure (a) of Figure 3 , in the reference posture of the deflection magnet 45A, the pair of protruding portions 49 extend from the wall portions of the main body portion 48 facing each other in the X-axis direction toward the beam axis CL. The pair of protruding portions 49 are arranged to face each other in the X-axis direction while sandwiching the beam pipe 21 from both sides in the X-axis direction. Coils 47 are provided on each of the protruding portions 49. Thus, in the reference posture, the deflection magnet 45A generates a magnetic field Ba in the X-axis direction. Thereby, the deflection magnet 45A generates a deflection force Fa in the Y-axis direction.

[0100] As Figure 3As shown in (b), in the reference posture of the deflection magnet 45B, a pair of protruding portions 49 extend from the walls of the main body portion 48 facing each other in the Y-axis direction toward the optical axis CL. The pair of protruding portions 49 are arranged so as to face each other in the Y-axis direction while sandwiching the optical fiber duct 21 from both sides in the Y-axis direction. Coils 47 are provided on each of the protruding portions 49. Thus, in the reference posture, the deflection magnet 45B generates a magnetic field Bb in the X-axis direction. Thereby, the deflection magnet 45B generates a deflection force Fb in the X-axis direction.

[0101] As Figure 3 shown in (c), in the reference posture, the deflection force Fa and the deflection force Fb are perpendicular to each other at 90°. When the magnitudes of the deflection force Fa and the deflection force Fb are equal, the combined deflection force Ft after overlapping the two acts in a direction at 45° with respect to the X-axis direction. In addition, in Figure 3 (a) to Figure 3 (c), the direction of the deflection force Fb is the positive side of the X-axis direction, but by changing the direction of the current flowing through the coil 47, it can be changed to the negative side of the X-axis direction. The direction of the deflection force Fa is the positive side of the Y-axis direction, but by changing the direction of the current flowing through the coil 47, it can be changed to the negative side of the Y-axis direction. In addition, the magnitudes of the deflection force Fa and the deflection force Fb can be changed by adjusting the magnitude of the current flowing through the coil 47. The deflection magnet device 30 can adjust the magnitude and direction of the combined deflection force Ft by adjusting the magnitudes and directions of the deflection force Fa and the deflection force Fb. The direction of the combined deflection force Ft can be adjusted by 360° around the optical axis CL. Among them, when changing the direction of the combined deflection force Ft in the state of the reference posture, when the magnitudes of the deflection force Fa and the deflection force Fb are the maximum, it is the maximum at the angles θ1 of 45°, 135°, 225°, and 315°. Sometimes the combined deflection force Ft at this time is referred to as the "maximum deflection force Fmax". In addition, the angle θ1 of the combined deflection force Ft is an angle based on the positive side of the X-axis direction. When the combined deflection force Ft is at an angle other than the above angle, it is necessary to reduce either the deflection force Fa or the deflection force Fb. Therefore, the magnitude of the combined deflection force Ft when the angle θ1 is other than the above angle becomes smaller than the magnitude of the maximum deflection force. When the angle θ1 is 0°, the deflection force Fa becomes 0, so the combined deflection force Ft is only the magnitude of the deflection force Fb. When the angle θ1 is 90°, the deflection force Fb becomes 0, so the combined deflection force Ft is only the magnitude of the deflection force Fa. Therefore, in the case of a structure (referred to as a comparative example) in which the angles of the deflection magnet 45A and the deflection magnet 45B around the optical axis CL cannot be changed from the reference posture, except for "angle θ1 = 45°, 135°, 225°, 315°", the maximum value of the combined deflection force Ft becomes smaller than the maximum deflection force Fmax. Figure 3The adjustment range AE of the synthetic deflection force Ft is shown in (c). In addition, the adjustment range AE of the comparative example is fixed around the beam axis CL.

[0102] In contrast, as Figure 4 (a) to Figure 4 (c) shows, the deflection magnets 45A and 45B of the deflection magnet device 30 of the present embodiment can rotate around the beam axis CL of the particle beam B. The deflection magnets 45A and 45B rotate around the beam axis CL as the rotation center. Thereby, the directions of the deflection forces Fa and Fb of the deflection magnets 45A and 45B can be changed with respect to the reference posture.

[0103] As a structure for rotating the deflection magnets 45A and 45B, the structure shown in Figure 4 (a) to Figure 4 (c) can be adopted. As shown in Figure 4 (a) and Figure 4 (b), the pair of deflection magnets 45A and 45B can rotate around the beam axis CL of the particle beam B in a state of being fixed to each other in the rotation direction. That is, the pair of deflection magnets 45A and 45B rotate around the beam axis CL in a state of being integrated with each other. In this case, the orientation and rotation angle of the rotation direction RDa of the deflection magnet 45A are the same as the orientation and rotation angle of the rotation direction RDb of the deflection magnet 45B. The deflection force Fa generated by the deflection magnet 45A acts in a direction rotated by an amount corresponding to the rotation angle with respect to the Y-axis direction. The deflection force Fb generated by the deflection magnet 45B acts in a direction rotated by an amount corresponding to the rotation angle with respect to the X-axis direction. Among them, the relationship that the deflection force Fa and the deflection force Fb are perpendicular to each other by 90° is maintained regardless of the rotation angle and orientation.

[0104] The method for fixing the pair of deflection magnets 45A and 45B to each other in the rotation direction is not particularly limited. For example, the main body 48 of the deflection magnet 45A and the main body 48 of the deflection magnet 45B may be fixed to each other by using a prescribed connecting member or the like. For example, the deflection magnets 45A and 45B can be fixed to a common base member. Alternatively, pins can be inserted into and fixed to the main body 48 of the deflection magnet 45A and the main body 48 of the deflection magnet 45B.

[0105] In this case, as Figure 4As shown in (c), the direction of the deflection force Fa can be changed by an amount corresponding to the rotation angle θ2 from the Y-axis direction, and the direction of the deflection force Fb can be changed by an amount corresponding to the rotation angle θ2 from the X-axis direction. In such a case, the maximum deflection force Fmax can also be generated at an angle other than "angle θ1 = 45°". Further, if the adjustment range of the rotation angle θ2 is set to at least 90°, then by adjusting the orientations of the deflection force Fa and the deflection force Fb, the maximum deflection force Fmax can be generated within the range of "angle θ1 = 0° to 360°". That is, the deflection magnet device 30 can adjust the magnitude of the combined deflection force Ft within the range of "0 to the maximum deflection force Fmax" during a full rotation around the beam axis CL. Therefore, the adjustment range AE is not fixed around the beam axis CL but is set as a range that rotates around the beam axis CL. Here, when the adjustment range of the particle beam B is limited to a certain extent, the adjustment range of the rotation angle θ2 only needs to be at least greater than 0°, and it can also be less than 90°.

[0106] As a structure for rotating the deflection magnet 45A and the deflection magnet 45B, the structure shown in (a) to Figure 5 of (a) to Figure 5 the structure shown in (c) of can be adopted. As shown in (a) of Figure 5 and (b) of Figure 5 , one of the pair of deflection magnets 45A and 45B can rotate around the beam axis CL of the particle beam B independently of the other. In the examples shown in (a) of Figure 5 and (b) of Figure 5 , the pair of deflection magnets 45A and 45B can rotate around the beam axis CL of the particle beam B in a mutually independent state. That is, the pair of deflection magnets 45A and 45B rotate around the beam axis CL in a mutually separated state. In such a case, the orientation and rotation angle of the rotation direction RDa of the deflection magnet 45A and the orientation and rotation angle of the rotation direction RDb of the deflection magnet 45B may also be different. The deflection force Fa generated by the deflection magnet 45A acts in a direction rotated by an amount corresponding to the rotation angle relative to the Y-axis direction. The deflection force Fb generated by the deflection magnet 45B acts in a direction rotated by an amount corresponding to the rotation angle relative to the X-axis direction. Different from the structure shown in (a) to Figure 4 of (a) to Figure 4 the angle between the deflection force Fa and the deflection force Fb can be other than 90°.

[0107] In such a case, as shown in (a) of Figure 5As shown in (c), the direction of the deflecting force Fa can be changed by an amount corresponding to the rotation angle θ3 from the Y-axis direction, and the direction of the deflecting force Fb can be changed by an amount corresponding to the rotation angle θ4 from the X-axis direction. The rotation angle θ3 and the rotation angle θ4 can be different from each other. In such a case, the maximum deflecting force Fmax can also be generated at an angle other than "angle θ1 = 45°". Further, if the adjustment ranges of the rotation angle θ3 and the rotation angle θ4 are set to at least 90°, then by adjusting the orientations of the deflecting force Fa and the deflecting force Fb, the maximum deflecting force Fmax can be generated in the range of "angle θ1 = 0° to 360°". That is, the deflecting magnet device 30 can adjust the magnitude of the combined deflecting force Ft in the range of "0 to the maximum deflecting force Fmax" over the entire circumference around the beam axis CL. The adjustment range AE is not limited to a square as in Figure 4 shown in (c), and as shown in Figure 5 shown in (c), all quadrilateral shapes can be formed according to the directions of the deflecting force Fa and the deflecting force Fb. Among them, when the adjustment range of the particle beam B is limited to a certain extent, the adjustment ranges of the rotation angle θ3 and the rotation angle θ4 only need to be at least greater than 0°, and can also be less than 90°.

[0108] Here, as shown in Figure 3 shown in (c), the angle between the deflecting force Fa and the maximum deflecting force Fmax, and the angle between the deflecting force Fb and the maximum deflecting force Fmax are fixed at 45°. Therefore, among the deflecting force Fa and the deflecting force Fb, the component Floss that does not contribute to the maximum deflecting force Fmax and cancels each other out becomes larger. The component Floss is also generated in the structure shown in Figure 4 shown in (a) to Figure 4 shown in (c). On the other hand, in the structure shown in Figure 5 shown in (a) to Figure 5 shown in (c), different from the structure shown in Figure 4 shown in (a) to Figure 4 shown in (c), the angle between the deflecting force Fa and the deflecting force Fb can also be less than 90°. In such a case, as shown in Figure 5 shown in (c), the angle between the deflecting force Fa and the maximum deflecting force Fmax, and the angle between the deflecting force Fb and the maximum deflecting force Fmax can be less than 45°. In such a case, the component Floss that cancels each other out among the deflecting force Fa and the deflecting force Fb can be reduced, and the directional component that contributes to the maximum deflecting force Fmax can be increased. Therefore, compared with the comparative example and the structure shown in Figure 4 shown in (a) to Figure 4 shown in (c), the deflecting magnet device 30 shown in Figure 5 shown in (a) to Figure 5 shown in (c) can increase the maximum deflecting force Fmax.

[0109] In addition, in a case where it is possible to anticipate in advance the adjustment of the direction of the particle beam B, there may be an operation such as fixing one of the deflection magnets 45A and 45B and rotating the other. For example, when the deflection magnet device 30 is disposed near the exit of the accelerator 3, the angle of the particle beam B in the vertical direction does not shift significantly, but sometimes it shifts significantly in the horizontal direction. In the said case, the deflection magnet 45B in the horizontal direction can be fixed and the other deflection magnet 45A can be rotated.

[0110] It may be: as Figure 6 shown in (a) of Figure 6 the deflection magnet device 30 has one deflection magnet 45C, and one deflection magnet 45C can rotate around the optical axis CL of the particle beam B. Even with one deflection magnet 45C, the degrees of freedom of two axes (angle and magnitude) can be ensured as the degrees of freedom for adjusting the deflection force Fc of the particle beam B. As

[0111] In Figure 3 (a) to Figure 3 (c) to Figure 6 (a) of Figure 6 (b) of the deflection magnet device 30 shown, the direction in which the optical axis CL extends is not particularly limited, and it may extend in the horizontal direction, may extend in a direction inclined from the horizontal direction, or may extend in the vertical direction. When the optical axis CL extends in the horizontal direction, the Z-axis direction and the X-axis direction become the horizontal direction, and the Y-axis direction becomes the vertical direction. The orientation of the magnetic field of the deflection magnet 45A in the comparative example (the orientation of the magnetic field in the optical axis CL), that is, the facing direction of the protruding portion 49, becomes the horizontal direction. In addition, the orientation of the magnetic field of the deflection magnet 45B, that is, the facing direction of the protruding portion 49, becomes the vertical direction. In contrast, as Figure 4 (a) to Figure 4 (c) to Figure 6 (a) of Figure 6 (b) shown, when adjusting by rotating the deflection magnet 45B around the optical axis CL, the orientation of the magnetic field of the deflection magnet 45B becomes an arrangement inclined with respect to the vertical direction. The orientation of the magnetic field of the deflection magnet 45A is not a direction orthogonal to the vertical direction (i.e., the horizontal direction), but becomes an arrangement inclined with respect to the vertical direction.

[0112] Next, referring to Figure 7 (a) of Figure 7 (b) to Figure 9 (a) of Figure 9Item (b) describes the mechanism for rotating the deflection magnet 45. In addition, the subsequent mechanisms can be applied to any of the deflection magnets 45A, 45B, and 45C. As Figure 7 in item (a), Figure 7 in item (b) - Figure 9 in item (a), Figure 9 as shown in item (b), the deflection magnet device 30 includes an adjustment mechanism 50 that adjusts the rotation angle of the deflection magnet 45 with respect to the optical axis CL.

[0113] Figure 7 in item (a), Figure 7 Item (b) is an example when the Y-axis direction is set to the vertical direction. That is, it is assumed that gravity acts toward the negative side of the Y-axis direction. Figure 7 The adjustment mechanism 50 shown in item (a) includes support portions 51A and 51B that support the deflection magnet 45 from below. The support portions 51A and 51B are arranged to be separated from each other in the X-axis direction and respectively support both end sides in the X-axis direction of the lower surface 45a of the deflection magnet 45. The support portions 51A and 51B have placement portions 51a for placing the lower surface 45a of the deflection magnet 45. The adjustment mechanism 50 adjusts the rotation angle of the deflection magnet 45 by adjusting the height of the placement portion 51a of the support portion 51A and the height of the placement portion 51a of the support portion 51B. The adjustment mechanism 50 can make the deflection magnet 45 in a reference posture by making the heights of the placement portions 51a of the support portions 51A and 51B the same (refer to Figure 3 in item (a) - Figure 3 item (c)). On the other hand, the adjustment mechanism 50 rotates the deflection magnet 45 by setting a difference in the heights of the placement portions 51a of the support portions 51A and 51B and maintains the posture at the rotated position.

[0114] Figure 7 The adjustment mechanism 50 shown in item (b) has a base member 52 that extends parallel to the XZ plane below the deflection magnet 45, and spacers 53A and 53B arranged on the base member 52. The spacers 53A and 53B are arranged to be separated from each other in the X-axis direction and respectively support both end sides in the X-axis direction of the lower surface 45a of the deflection magnet 45. The adjustment mechanism 50 adjusts the rotation angle of the deflection magnet 45 by adjusting the thickness of the spacer 53A and the thickness of the spacer 53B. The adjustment mechanism 50 can make the deflection magnet 45 in a reference posture by making the thicknesses of the spacers 53A and 53B the same (refer to Figure 3 in item (a) - Figure 3On the other hand, the adjustment mechanism 50 rotates the deflection magnet 45 by setting a difference in the thicknesses of the spacers 53A and 53B, and maintains the posture at the rotated position.

[0115] As Figure 8 shown in (a) of [], the adjustment mechanism 50 using the pin 54 can be adopted. As Figure 8 shown in (a) of [], the adjustment mechanism 50 has a receiving portion 56 and a pin 54 provided on the negative side in the Y-axis direction of the deflection magnet 45. A plurality of receiving holes 56a are formed in the receiving portion 56 at a predetermined interval around the light beam axis CL. The receiving holes 56a receive the pin 54. Further, the receiving holes 56a and the pin 54 extend in the Z-axis direction. In the adjustment mechanism 50, the deflection magnet 45 and the receiving portion 56 are rotated at a desired angle. At this time, the pin 54 is inserted into any one of the receiving holes 56a of the receiving portion 56. At this time, inside the receiving hole 56a, it communicates with other receiving holes formed in other base members or the like. Therefore, by inserting the pin 54 through the receiving hole 56a and other receiving holes, the pin 54 fixes the receiving portion 56 and the deflection magnet 45 together at the rotated position.

[0116] As Figure 8 shown in (b) of [], the adjustment mechanism 50 using the engaging portion 57a can be adopted. As Figure 8 shown in (b) of [], the adjustment mechanism 50 has an engaging member 57 and a support member 58 provided on the negative side in the Y-axis direction of the deflection magnet 45. The engaging member 57 has a plurality of engaging portions 57a provided at a predetermined interval around the light beam axis CL at the end portion on the negative side in the Y-axis direction. The plurality of engaging portions 57a are formed of a repeating pattern of ridges and valleys. In the adjustment mechanism 50, the deflection magnet 45 and the engaging member 57 are rotated at a desired angle. At this time, the support member 58 is engaged with any one of the engaging portions 57a of the engaging member 57. At this time, by supporting the engaging portion 57a in a state of being engaged with the support member 58, the engaging member 57 and the deflection magnet 45 are fixed together at the rotated position.

[0117] As Figure 9 shown in (a) of [], the adjustment mechanism 50 using the gear 60 can be adopted. As Figure 9 shown in (a) of [], the adjustment mechanism 50 has a gear 60 fixed to the deflection magnet 45 and a gear 61 meshing with the gear 60. The gear 61 is fixed to the rotating shaft 62 and rotates together with the rotating shaft 62. The adjustment mechanism 50 rotates the deflection magnet 45 via the gear 60 by rotating the gear 61. The gear 61 is stopped at the position where the deflection magnet 45 reaches the desired rotation angle. Thereby, the deflection magnet 45 maintains the posture at the rotation angle position. By using the gear 60 in this way, the rotation angle can be adjusted steplessly.

[0118] AsFigure 9 As shown in Fig. (b), an adjustment mechanism 50 using a pinion 63 can be adopted. As Figure 9 shown in Fig. (b), the adjustment mechanism 50 has a gear 60 fixed to the deflection magnet 45 and a pinion 63 meshing with the gear 60. The pinion 63 is fixed to the rotating shaft 62 and rotates together with the rotating shaft 62. The adjustment mechanism 50 moves the pinion 63 in the X-axis direction, and rotates the deflection magnet 45 via the gear 60. The pinion 63 is stopped at the position where the deflection magnet 45 reaches the desired rotation angle. Thus, the deflection magnet 45 maintains its posture at the rotation angle position. By using the gear 60 in this way, the rotation angle can be adjusted steplessly.

[0119] The adjustment mechanism 50 may include a drive unit 65 for rotating the deflection magnet 45 relative to the beam axis CL. In Figure 9 the example shown in Fig. (a), the adjustment mechanism 50 may have a drive unit 65 such as a motor for rotating the rotating shaft 62. In Figure 9 the example shown in Fig. (b), the adjustment mechanism 50 may have a drive mechanism 64 for reciprocally moving the pinion 63 in the X-axis direction as the drive unit 65. In addition, Figure 9 the gear 61 in Fig. (a) and Figure 9 the pinion 63 in Fig. (b) can also be moved manually by an operator without depending on the drive unit 65. In addition, Figure 7 the support portions 51A and 51B in Fig. (a) can be adjusted manually by an operator or can be adjusted by a drive unit. As Figure 7 shown in Fig. (b) and Figure 8 Fig. (a), Figure 8 shown in Fig. (b), the rotation of the deflection magnet 45 and the operation of fixing it at the rotation angle can be performed manually by an operator, or a mechanism for making it operate can be provided and it can be operated by a drive unit.

[0120] The adjustment of the deflection of the particle beam B of the deflection magnet device 30 can also be performed by the control unit 7 (see Figure 2 ). In addition, the control unit 7 can control the rotation angle of the deflection magnet 45 by controlling the drive unit. The control unit 7 can Figure 4 Fig. (a) to Figure 4 Fig. (c) and Figure 5 Fig. (a) to Figure 5The structure shown in (c) is adjusted in two stages. The control unit 7 makes the deflection magnet 45 rotate to perform the first adjustment of the particle beam B. In the first adjustment, a rough adjustment for adjusting the general angle is performed. The control unit 7 performs the second adjustment of the particle beam B by electrically controlling the deflection magnet 45. In the second adjustment, the direction of the combined deflection force Ft is adjusted by adjusting the currents with respect to the deflection magnets 45A and 45B. In the second adjustment, fine adjustment is performed. In Figure 6 of (a), Figure 6 In the structure shown in (b), the control unit 7 adjusts the deflection direction by adjusting the rotation angle of the deflection magnet 45C. In addition, these adjustments can also be manually performed by an operator without depending on the control of the control unit 7.

[0121] In addition, the structure of the deflection magnet device 30 only needs to be applied to at least one of the deflection magnet devices 30A, 30B, and 30C. In addition, in Figure 1 , a pair of deflection magnets 40 are described in the deflection magnet device 30A, but Figure 6 of (a), Figure 6 the structure shown in (b) can also be used as one deflection magnet 40. In addition, one deflection magnet is described in the deflection magnet devices 30B and 30C, but Figure 4 of (a) to Figure 4 of (c) and Figure 5 of (a) to Figure 5 of (c) can also be used as a pair of deflection magnets.

[0122] Next, the operations and effects of the particle beam therapy device 1, the deflection magnet device 30, and the particle beam adjustment method of the present embodiment will be described.

[0123] According to the particle beam therapy device 1, the deflection magnet 45 that deflects the particle beam B of the transport unit 20 can rotate around the optical axis CL of the particle beam B. In this case, the deflection magnet 45 can be rotated around the optical axis CL in accordance with the desired deflection direction of the particle beam B. Therefore, the direction of the deflection force of the deflection magnet 45 can be effectively obtained to be consistent with the desired deflection direction of the particle beam B. Based on the above, the deflection force can be effectively obtained regardless of the deflection direction of the particle beam B. In addition, by obtaining an effective deflection force, compared with the non-rotating deflection magnet device of the comparative example, even if the deflection magnet 45 is reduced, the desired performance can be obtained. In this way, cost reduction can be achieved by reducing the deflection magnet 45. In addition, when adjusting the rotation angle of the deflection magnet 45 itself, compared with the case of adjusting the deflection direction only by an electrical method, the adjustment operation process can be reduced, and thus cost reduction can also be achieved.

[0124] It can be: The deflection magnet device 30 has a pair of deflection magnets 45A and 45B. The pair of deflection magnets 45A and 45B can rotate around the optical axis CL of the particle beam B while being fixed to each other in the rotational direction. When the deflection forces of the pair of deflection magnets 45A and 45B are made to coincide, an angle where the deflection force involved in the coincidence is large and an angle where the deflection force becomes small are formed. For example, as shown in (c) of Figure 3 , when the angle θ1 is 45°, the resultant deflection force Ft can be made the maximum deflection force Fmax, but when the angle θ1 is 0° or 90°, the resultant deflection force Ft can only obtain the magnitude of one deflection force. In contrast, by rotating the pair of deflection magnets 45A and 45B around the optical axis CL of the particle beam B, the direction where a large deflection force can be ensured (for example, the direction where the maximum deflection force Fmax is obtained) can be made to coincide with the desired deflection direction of the particle beam B. Therefore, regardless of the deflection direction of the particle beam B around the optical axis CL, a large deflection force of the pair of deflection magnets 45A and 45B can be ensured. Here, since the pair of deflection magnets 45A and 45B are in a state of being fixed to each other in the rotational direction, the adjustment of the rotational angle can be easily performed compared to the case of individually adjusting the rotational angles of the pair of deflection magnets 45A and 45B.

[0125] It can be: The deflection magnet device 30 has a pair of deflection magnets 45A and 45B. One of the pair of deflection magnets 45A and 45B can rotate around the optical axis of the particle beam independently of the other. When the deflection forces of the pair of deflection magnets 45A and 45B are made to coincide, an angle where the deflection force involved in the coincidence is large and an angle where the deflection force becomes small are formed. By rotating the pair of deflection magnets 45A and 45B around the optical axis of the particle beam, the direction where a large deflection force can be ensured can be made to coincide with the desired deflection direction of the particle beam. Therefore, regardless of the deflection direction of the particle beam B around the optical axis CL, a large deflection force of the pair of deflection magnets 45A and 45B can be ensured. Here, when the deflection force of one of the deflection magnets 45A coincides with the deflection force of the other deflection magnet 45B, there are direction components such as the two deflection forces canceling each other out (refer to the component Floss in (c) of Figure 3 ). In contrast, one of the pair of deflection magnets 45A and 45B can rotate around the optical axis CL of the particle beam B independently of the other. Therefore, the relative rotational angles of the respective deflection magnets 45A and 45B can be adjusted to reduce the direction components that cancel each other out. Thereby, the energy of the deflection magnet device 30 can be effectively utilized.

[0126] It can be: The deflection magnet device 30 has a single deflection magnet 45C. The single deflection magnet 45C can rotate around the optical axis CL of the particle beam B. In such a case, the number of magnets of the deflection magnet device 30 can be reduced.

[0127] It is possible that the particle beam therapy device 1 includes an adjustment mechanism 50 that adjusts the rotation angle of the deflection magnet 45 relative to the beam axis CL. In this case, by using the adjustment mechanism 50, the rotation angle of the deflection magnet 45 can be easily and accurately adjusted.

[0128] It is possible that the adjustment mechanism 50 includes a drive unit 60 that rotates the deflection magnet 45 relative to the beam axis CL. In this case, the rotation angle of the deflection magnet 45 can be adjusted without relying on manual work by an operator.

[0129] It is possible that the beam axis CL extends in the horizontal direction, and the orientation of the magnetic field of the deflection magnet 45 is inclined with respect to the vertical direction.

[0130] It is possible that the particle beam therapy device 1 further includes a control unit 7 that controls the deflection magnet device 30. The control unit 7 performs a first adjustment of the particle beam B by rotating the deflection magnet 45. In this case, by rotating the deflection magnet 45 itself, the control unit 7 can roughly adjust the direction of the deflection force.

[0131] The control unit 7 performs a second adjustment of the particle beam B by electrically controlling the deflection magnet 45. In this case, the control unit 7 can finely adjust the direction of the deflection force.

[0132] It is possible that the deflection magnet device 30 has a pair of deflection magnets 45A and 45B. In the first adjustment, the control unit 7 rotates each of the deflection magnets 45A and 45B relative to each other. In this case, the control unit 7 can also adjust the angle between the pair of deflection magnets 45A and 45B through the first adjustment.

[0133] The deflection magnet device 30 of the present embodiment includes a deflection magnet 45 that deflects the particle beam B. In the deflection magnet device 30, the deflection magnet 45 can rotate around the beam axis CL of the particle beam B.

[0134] According to the deflection magnet device 30, by being provided at the position where the particle beam B passes, the particle beam B can be deflected in a desired direction. At this time, the deflection magnet 45 can be rotated around the beam axis CL in accordance with the desired deflection direction of the particle beam B. Therefore, the direction of the deflection force effectively obtained by the deflection magnet 45 can be made to coincide with the desired deflection direction of the particle beam B. Based on the above, the deflection force can be effectively obtained regardless of the deflection direction of the particle beam B.

[0135] The particle beam adjustment method of the present embodiment adjusts a deflection magnet that deflects the particle beam B. In the particle beam adjustment method, the particle beam is adjusted by rotating the deflection magnet around the beam axis of the particle beam.

[0136] According to the particle beam adjustment method, by disposing a deflection magnet 45 at a position where the particle beam B passes, the particle beam B can be deflected in a desired direction. At this time, the deflection magnet 45 is rotated around the optical axis CL in accordance with the deflection direction of the desired particle beam B. Therefore, the direction in which the deflection force of the deflection magnet is effectively obtained can be made to coincide with the deflection direction of the desired particle beam B. Based on the above, the deflection force can be effectively obtained regardless of the deflection direction of the particle beam B.

[0137] The present invention is not limited to the above-described embodiments.

[0138] In Figure 1 the cyclotron is exemplified as an accelerator, but the structure of the present invention can also be adopted for various accelerators such as a synchrocyclotron and a linear accelerator (LINAC).

[0139] In the above-described embodiment, the deflection magnet device 30 is applied to the transport section of the particle beam treatment device, but the application destination is not particularly limited. For example, the deflection magnet device 30 can be applied to a high-energy accelerator. In addition, the deflection magnet device 30 can be applied to an experimental device for charged particle beams. In addition, the deflection magnet device 30 can be applied to a magnetic separator.

Claims

1. A particle beam therapy device, comprising: An irradiation unit irradiates a particle beam to an irradiated object; A conveying unit, for conveying the particle beam; as well as The deflection magnet device includes a deflection magnet for deflecting the particle beam of the transport unit, wherein the deflection magnet is rotatable around a beam axis of the particle beam.

2. The particle beam therapy device according to claim 1, wherein The deflection magnet device comprises a pair of deflection magnets. The pair of deflection magnets are rotatable around the beam axis of the particle beam in a state where the rotational directions are fixed to each other.

3. The particle beam therapy device according to claim 1, wherein The deflection magnet device comprises a pair of deflection magnets. One of the pair of deflection magnets is rotatable around a beam axis of the particle beam independently of the other.

4. The particle beam therapy device according to claim 1, wherein The deflection magnet device comprises a deflection magnet, One of the deflection magnets is rotatable about the beam axis of the particle beam. 5 . The particle beam therapy apparatus according to claim 1 , comprising an adjustment mechanism for adjusting a rotation angle of the deflection magnet relative to the beam axis. 6 . The particle beam therapy apparatus according to claim 5 , wherein the adjustment mechanism comprises a driving unit configured to rotate the deflection magnet relative to the beam axis. 7 . The particle beam therapy apparatus according to claim 2 , wherein the beam axis extends in a horizontal direction, and the direction of the magnetic field of the deflection magnet is inclined with respect to a vertical direction.

8. The particle beam therapy device according to claim 1, further comprising a control unit configured to control the deflection magnet device. The control unit performs a first adjustment of the particle beam by rotating the deflection magnet. 9 . The particle beam therapy apparatus according to claim 8 , wherein the control unit performs the second adjustment of the particle beam by electrically controlling the deflection magnet.

10. The particle beam therapy device according to claim 8, wherein The deflection magnet device comprises a pair of deflection magnets. In the first adjustment, the control unit causes the deflection magnets to rotate relative to each other.

11. A deflection magnet device, comprising a deflection magnet for deflecting a particle beam, wherein: The deflection magnet is rotatable about a beam axis of the particle beam.

12. A particle beam adjustment method, comprising adjusting a deflection magnet for deflecting a particle beam, wherein: The particle beam is steered by rotating the deflection magnet about a beam axis of the particle beam.

Images