JP2008307206A - Particle beam irradiation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a particle beam irradiation system which can prevent charged particle beams from getting wrongly emitted. <P>SOLUTION: Charged particle beams accelerated by a particle beam accelerator 2 are transported to a particle beam emitter 3 along a prescribed route by a particle beam transporter 4. The particle beam emitter 3 emits charged particle beams passing prescribed routes to a target of irradiation. The particle beam transporter 4 has a path branching portion 5. The path branching portion 5 has a deflector 8 comprising a deflection permanent magnet 14 and deflection electromagnets 15 and 16 and a power supply supplying electricity to an electromagnetic coil forming a deflection electromagnet for excitation of the deflection electromagnets 15 and 16. When the deflection electromagnets 15 and 16 are excited, the path of in-transit charged particles gets on a path where the charged particles are transported in the position where the particle beam emitter 3 is installed. When the deflection electromagnets 15 and 16 are not excited, the path of in-transit charged particles is branched to a path different from one where charged particles are transported to the position where the particle beam emitter 3 is installed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a particle beam irradiation system that irradiates an irradiation target such as an affected part of a patient with a charged particle beam.

A charged particle beam accelerated to a predetermined energy by a particle beam accelerator is placed at a predetermined position by a particle beam transport line (hereinafter referred to as a transport device) having a group of deflecting magnets, a quadrupole magnet, and the like. It is used for the purpose of curing cancer by irradiating an irradiation object such as a cancer tissue via an irradiation device and destroying the cancer tissue.
When irradiating an irradiation target, erroneous irradiation is prevented by ON / OFF control of the irradiated particle beam. As a means for this ON / OFF control, for example, a method of providing a kicker electromagnet in a transporting device transported to the irradiation device and stopping / starting the transport of the particle beam to the irradiation device is generally used. When the particle beam transport is stopped, the kicker electromagnet is excited. The particle beam is deflected by the excitation of the kicker electromagnet, is directed in a direction different from that of the irradiation device, and is received and stopped by the particle beam blocking block installed there. On the other hand, when the transport of the particle beam to the irradiation device is started, excitation of the kicker electromagnet is stopped. Thereby, the deflection of the particle beam is released, and the particle beam is transported to the irradiation device (see, for example, Non-Patent Document 1).

by Eros Pedroni et al., "The 200-MeV proton therapy project at the paul Scherrer Institute: Conceptual design and practical realization", Medical Physics, Volume 22 (1), January 1995, Page 37-53

  In this system, when the kicker electromagnet is not normally excited due to a failure of the kicker magnet, the particle beam is erroneously sent to the irradiation device even if the control for stopping the transport of the particle beam is performed on the kicker magnet. .

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain a particle beam irradiation system capable of preventing erroneous irradiation of a charged particle beam.

  A particle beam generator for generating a charged particle beam, a particle beam accelerator for accelerating the charged particle beam, a duct through which the accelerated charged particle beam travels, and the accelerated charged particle beam A transport device for transporting to a position, and a particle beam irradiation device for adjusting the characteristics of the charged particle beam that has been transported and irradiating the irradiation target, the transport device comprising a deflection permanent magnet and a deflection electromagnet Charged particles being transported when the deflection electromagnet has an orbit branching section including a deflection device and a power supply device for supplying power to the electromagnetic coil constituting the deflection electromagnet for exciting the deflection electromagnet Is placed on the trajectory where charged particles are transported to the position where the particle beam irradiation device is installed, and when the deflecting electromagnet is not excited, the trajectory of the charged particles being transported is installed on the particle beam irradiation device. The Particle beam irradiation system, characterized in that the the trajectory charged particles are transported to a position in which branches in different orbits.

  In the particle beam irradiation system according to the present invention, the particle beam is deflected in a direction different from that of the irradiation device by stopping the excitation of the electromagnet, and the charged particles are deflected in a direction along a predetermined path by the excitation of the electromagnet. Therefore, when an abnormality such as a power failure or a power failure occurs, the particle beam is deflected in a direction different from that of the particle beam irradiation device, and charged particles to the particle beam irradiation device are transported to the particle beam irradiation device. It is possible to prevent erroneous irradiation of the charged particle beam by preventing erroneous transport of the beam.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a particle beam treatment system which is an example of a particle beam irradiation system according to Embodiment 1 of the present invention. In the figure, a particle beam therapy system includes a particle beam generator 1 that generates a charged particle beam (charged particle beam), a particle beam accelerator 2 that accelerates a charged particle beam from the particle beam generator 1, and a particle beam acceleration. A particle beam irradiation apparatus 3 that irradiates an irradiation target (for example, an affected part of a patient) with a charged particle beam accelerated by the apparatus 2, and a particle beam transport that transports the charged particle beam from the particle beam acceleration apparatus 2 to the particle beam irradiation apparatus 3. An apparatus (particle beam transport line) 4 and a control device 6 for controlling each of the particle beam generator 1, the particle beam accelerator 2, the particle beam irradiation device 3, and the particle beam transport device 4 are included.

  The particle beam generator 1 includes an ion source that generates charged particles (for example, hydrogen ions (H +) and carbon ions (C + 6)), and a charged particle beam (for example, proton beam or And a pre-accelerator for a carbon beam or the like. The charged particle beam generated by the particle beam generator 1 is sent to the particle beam accelerator 2. The particle beam accelerator 2 gives energy to the charged particle beam from the particle beam generator 1 to accelerate the charged particle beam. The energy of the charged particle beam is increased to several hundred megavolts by the particle beam accelerator 2.

  The particle beam transport device 4 includes a vacuum duct through which the charged particle beam passes, a deflection electromagnet that normally deflects the charged particle beam along the vacuum duct, and a quadrupole electromagnet that suppresses the divergence of the charged particle beam. Further, the particle beam transport apparatus 4 has an orbit branching section 5 that can selectively deflect a charged particle beam. The inside of the vacuum duct is kept in a vacuum state. The charged particle beam is transported from the particle beam accelerating device 2 to the particle beam irradiation device 3 by passing through the vacuum duct along a predetermined path (that is, transport trajectory). Not only the particle beam transport device 4 but also the particle beam accelerator 2 and the particle beam irradiation device 3 are maintained in a vacuum state.

  The particle beam irradiation apparatus 3 irradiates the irradiation target with a charged particle beam passing through a predetermined path. The particle beam irradiation device 3 adjusts the energy of the charged particle beam received from the particle beam transport device 4 according to the depth of the irradiation target, or changes the dose, shape, etc. of the charged particle beam to the shape of the irradiation target. There are provided a plurality of adjusting devices that adjust together, and a plurality of monitor devices that monitor the dose, shape, and the like of the charged particle beam irradiated to the irradiation target. Scanning electromagnets, scatterers, collimators, range shifters, and the like are used as the adjustment devices. An irradiation vacuum window through which a charged particle beam can pass is provided at the end of the particle beam irradiation apparatus 3. The irradiation vacuum window is made of, for example, an aluminum thin film having a predetermined thickness (0.1 mm or more). The charged particle beam irradiates the irradiation target by jumping out of the particle beam irradiation apparatus 3 through the irradiation vacuum window. Irradiation of the charged particle beam by the particle beam irradiation device 3 is performed after the setting values (each parameter) of each adjustment device and each monitor device are adjusted by the control device 6 according to a predetermined procedure.

  The orbital branching unit 5 includes a deflecting device 8 composed of a deflecting electromagnet and a deflecting permanent magnet arranged so as to surround the vacuum duct of the particle beam transport device 4, and a power supply device that supplies power to the deflecting electromagnet. It is provided between the charged particle beam incident end of the particle beam transport device 4 and the exit end to the particle beam irradiation device 3. As a result, the charged particle beam when transported by the particle beam transport device 4 passes through the installation location of the deflection magnet belonging to the orbital branching section 5. The orbital branching unit 5 receives the irradiation stop command from the control device 6 and stops the power supply to the deflecting electromagnet from the power supply device, changes the traveling direction of the charged particle beam and changes the charged particle beam to the particle beam irradiation device 3. By blocking the passage and releasing the irradiation stop command from the control device 6, power is supplied to the deflection electromagnet from the power supply device, and the traveling direction of the charged particle beam is returned to the predetermined trajectory to the particle beam irradiation device 3. Is allowed to pass.

  FIG. 2 is a configuration diagram showing the track branching unit 5. The vacuum duct of the particle beam transport device 4 includes a branching portion vacuum duct 7 provided at a portion where the track branching portion 5 is installed. As described above, the orbital branching unit 5 includes a deflection device 8 including a deflection electromagnet that generates a magnetic field for deflecting the charged particle beam passing through the branching unit vacuum duct 7 and a deflection permanent magnet, and the deflection device 8. And a power supply device that feeds power to the constituting deflection electromagnet. Further, a particle beam blocking block 9 for blocking and stopping the charged particle beam is disposed so as to prevent the charged particle beam from passing through the particle beam irradiation apparatus 3.

  The branch vacuum duct 7 is often made of the same material as the vacuum duct constituting the particle beam transport device 4 (usually made of SUS or aluminum), but is adjacent to the deflection device 8 of the branch vacuum duct 7. You may comprise the site | part to do with nonelectroconductive materials (for example, glass, ceramics, etc.). Thereby, generation | occurrence | production of an eddy current in the branch part vacuum duct 7 by the magnetic field from the deflection | deviation apparatus 8 can be suppressed, and the electromagnetic force to the direction which prevents the traveling of the charged particle beam which arises by generation | occurrence | production of an eddy current is suppressed. be able to. The branching vacuum duct 7 has a tubular main duct 10 arranged along a predetermined path along which the charged particle beam is transported, and a tubular branching duct 11 branched from an intermediate portion of the main duct 10. ing. Note that all of the branch vacuum duct 7 may be made of a non-conductive material, or only a portion that receives a magnetic field from the deflecting device 8 (a part of the branch vacuum duct 7) is made of a non-conductive material. The same effects as described above can be obtained. Moreover, the branching part vacuum duct 7 may be comprised with the thin plate of metals (for example, stainless steel, aluminum, etc.).

  The main duct 10 communicates between the upstream and downstream vacuum ducts. At both ends of the main duct 10, flanges 12 connected to the respective vacuum ducts are provided. A branch part vacuum window 13 is provided at the front end of the branch duct 11 for holding the vacuum in the vacuum duct. The branch vacuum window 13 is made of, for example, an aluminum thin film having a predetermined thickness (0.1 mm or the like), and normally has no ability to block charged particles. Therefore, the charged particle beam guided to the branch duct 11 is used. In this state, the light passes through the branch portion vacuum window 13 and jumps out of the branch duct 11.

  In the example shown in FIG. 2, the particle beam blocking block 9 is from a predetermined route (a horizontal direction in FIG. 2, a particle beam trajectory that travels from left to right and reaches the particle beam irradiation device 3). It is arranged on the downstream side of the branching part vacuum window 13 on the off-path, that is, the path passing through the branching duct 11. The charged particle beam that has passed through the branching part vacuum window 13 and jumped out of the branching duct 11 is received by the particle beam blocking block 9. The particle beam blocking block 9 includes a first blocking block 25 and a second blocking block 26 disposed on the downstream side of the first blocking block 25. The first blocking block 25 is made of a material (for example, carbon or aluminum) having a predetermined shielding property against the charged particle beam. The second blocking block 26 is shielded against electromagnetic waves having a higher density than the first blocking block 25 in order to shield electromagnetic waves having high penetrating power generated when the charged particle beam is blocked by the first blocking block 25. It is comprised with high material (for example, copper etc.).

  The deflecting device 8 is disposed around the main duct 10 and upstream of the branch position of the branch duct 11. The deflecting device 8 generates a magnetic field that always deflects the charged particle beam and generates a magnetic field that deflects the charged particle beam only when receiving power (first excitation). It has an electromagnet 15 and a second deflection electromagnet 16 (a pair of deflection electromagnets). The first deflection electromagnet (one deflection electromagnet) 15, the deflection permanent magnet 14, and the second deflection electromagnet (the other deflection electromagnet) 16 are arranged in this order in the traveling direction of the charged particle beam.

  The direction 17 of the magnetic field by the first deflection electromagnet 15 (in FIG. 2, the direction going from the front side to the back side of the page) and the direction 18 of the magnetic field by the second deflection electromagnet 16 are the same direction. The direction 19 of the magnetic field by the deflection permanent magnet 14 (in FIG. 2, the direction going from the back side to the front side of the page) is the direction 17 of the magnetic field by the first deflection electromagnet 15 and the direction 18 of the magnetic field by the second deflection electromagnet 16. In the opposite direction. That is, the direction in which the charged particle beam is deflected by the respective magnetic fields of the first deflection electromagnet 15 and the second deflection electromagnet 16 is opposite to the direction in which the charged particle beam is deflected by the magnetic field of the deflection permanent magnet 14. Power supply to the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped when the power supply device of the orbit branching unit 5 receives the irradiation stop command, and when the power supply device of the orbit branching unit 5 releases the irradiation stop command. Be started.

  When power supply to the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped (excitation of each of the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped), only the magnetic field of the deflection permanent magnet 14 is used. Is generated in the main duct 10. At this time, the charged particle beam is deflected from the direction (pre-deflection direction) 20 along the main duct 10 to the direction (branch direction) 21 guided into the branch duct 11 only by the magnetic field of the deflection permanent magnet 14. That is, the charged particle beam is deflected from the pre-deflection direction 20 along the predetermined path to the branch direction 21 by passing through the deflecting device 8, and as a result, strikes the particle beam blocking block 9.

  When the first deflection electromagnet 15 and the second deflection electromagnet 16 are supplied with power (each of the first deflection electromagnet 15 and the second deflection electromagnet 16 is excited), the deflection permanent magnet 14 and the first deflection electromagnet 15 are used. And the magnetic field of each of the 2nd deflection electromagnets 16 is generated in the main duct 10. The charged particle beam is deflected in the direction 22 by the magnetic field of the first deflection electromagnet 15 from the pre-deflection direction 20, then deflected in the direction 23 by the magnetic field of the deflection permanent magnet 14, and further by the magnetic field of the second deflection electromagnet 16. The direction 23 is deflected in a direction (passing direction) 24 that passes through the main duct 10. That is, when power is supplied to each of the first deflection electromagnet 15 and the second deflection electromagnet 16, the charged particle beam changes the magnetic fields of the first deflection electromagnet 15, the deflection permanent magnet 14, and the second deflection electromagnet 16. By sequentially passing, the charged particle beam deviates from the particle beam blocking block 9 and is deflected in a passing direction 24 along a predetermined path.

  In this example, the passing direction 24 of the charged particle beam is the same direction as the pre-deflection direction 20. The absolute value of the deflection angle by the deflection permanent magnet 14 and the total absolute value of the deflection angles by the first deflection electromagnet 15 and the second deflection electromagnet 16 are equal to each other.

  The first deflecting electromagnet 15 and the second deflecting electromagnet 16 each have an electromagnetic coil through which a current flows by power supply, and generates a magnetic field by the current flowing through each electromagnetic coil. Each electromagnetic coil may be a coreless air core coil. The first deflection electromagnet 15 and the second deflection electromagnet 16 are supplied with power from a common power source and are connected in parallel to the power source.

  Particles that detect a charged particle beam received by the particle beam blocking block 9 (that is, a charged particle beam deflected toward the particle beam blocking block 9) are interposed between the branch vacuum window 13 and the particle beam blocking block 9. A line detector 27 may be arranged. The particle beam detection device 27 outputs a detection signal to the control device 6 by detecting the charged particle beam. As the particle beam detector 27, for example, an ionization chamber, a secondary electron detector, a scintillation detector, or the like is used.

  The control device 6 controls the operation of the system based on information from each of the monitor device provided in the particle beam irradiation device 3 and the particle beam detection device 27. That is, the control device 6 outputs an irradiation stop command to the power supply device of the trajectory branching unit 5 when the irradiation amount of the charged particle beam obtained from the information from the monitor device reaches a preset set amount. In addition, the control device 6 detects the particles when the time difference between when the irradiation stop command is output and when the detection signal from the particle beam detection device 27 is received exceeds a predetermined threshold (for example, 100 microseconds). Control for stopping the operation of the beam generator 1 and the particle beam accelerator 2 can be performed.

  The control device 6 includes a computer having an arithmetic processing unit (CPU), a storage unit (ROM, RAM, etc.) and a signal input / output unit. A program for realizing the function of the control device 6 is stored in the storage unit of the computer. The arithmetic processing unit reads a program stored in the storage unit, and executes arithmetic processing related to the function of the control device 6 based on the program.

  Next, the operation will be described. The charged particle beam is generated by the particle beam generator 1 under the control of the controller 6 and accelerated to a predetermined speed by the particle beam accelerator 2. Thereafter, the charged particle beam is transported by the particle beam transport device 4 and enters the main duct 10 at a position corresponding to the installation position of the deflecting device 8 of the orbital branching section 5 on the way.

  When stopping irradiation of the charged particle beam from the particle beam irradiation device 3, an irradiation stop command is sent from the control device 6 to the orbit branching unit 5. In the orbit branching unit 5, power supply from the power supply device to the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped. Thereby, the generation of the respective magnetic fields of the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped, and only the magnetic field of the deflection permanent magnet 14 is generated in the main duct 10.

  If the charged particle beam enters the main duct 10 while the generation of the respective magnetic fields of the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped, the charged particle beam is deflected from the pre-deflection direction 20 to the branch direction 21. Is done. The charged particle beam is guided into the branch duct 11, passes through the branch portion vacuum window 13, and jumps out of the branch duct 11. Thereafter, the charged particle beam is received by the particle beam blocking block 9 and the passage of the charged particle beam to the particle beam irradiation device 3 via the orbital branching unit 5 of the charged particle beam is blocked. The irradiation with the charged particle beam from the particle beam irradiation device 3 is stopped because the beam irradiation device 3 cannot be reached.

  When the irradiation of the charged particle beam from the particle beam irradiation device 3 is started, the control device 6 controls each parameter of each adjustment device and each monitor device provided in the particle beam irradiation device 3 to a predetermined value. The Thereafter, after the control device 6 confirms that the entire system is normal, power supply to each of the first deflection electromagnet 15 and the second deflection electromagnet 16 is started under the control of the control device 6.

  When power supply to each of the first deflection electromagnet 15 and the second deflection electromagnet 16 is started, the magnetic fields of the first deflection electromagnet 15, the deflection permanent magnet 14, and the second deflection electromagnet 16 are present in the main duct 10. appear. The charged particle beam that has entered the main duct 10 is deflected in the order of the pre-deflection direction 20, the direction 22, the direction 23, and the passage direction 24. The charged particle beam that has passed through the orbital branching unit 5 reaches the particle beam irradiation device 3 and jumps out of the particle beam irradiation device 3 from the irradiation vacuum window to be irradiated onto the irradiation target.

  When the irradiation amount of the charged particle beam reaches a preset amount, an irradiation stop command is output from the control device 6 to the orbit branching unit 5. When the orbital branching unit 5 receives the irradiation stop command, power supply from the power supply device to each of the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped, and the direction of the charged particle beam changes from the pre-deflection direction 20 to the branching direction 21. Change. The charged particle beam is guided into the branch duct 11 and jumps out of the branch duct 11 from the branch portion vacuum window 13. The charged particle beam that has jumped out of the branch duct 11 is detected by the particle beam detector 27 and then received by the particle beam blocking block 9. Thereby, irradiation of the charged particle beam from the particle beam irradiation apparatus 3 is stopped.

  Execution and stop of the irradiation of the charged particle beam from the particle beam irradiation device 3 are switched at high speed (for example, an interval of 0.1 msec or less) under the control of the trajectory branching unit 5 by the control device 6. When the charged particle beam is detected by the particle beam detection device 27, a detection signal is output from the particle beam detection device 27 to the control device 6. In the control device 6, it is determined whether or not the time difference between when the irradiation stop command is output and when the detection signal is received exceeds a predetermined threshold value. When the detection signal is not received by the control device 6 within the predetermined threshold time despite the irradiation stop command being output from the control device 6, the operation of the particle beam generator 1 and the particle beam accelerator 2 is controlled by the control device. It is stopped by the control 6. Thereby, erroneous irradiation of the charged particle beam from the particle beam irradiation apparatus 3 is prevented. This means that if the time difference is larger than a predetermined threshold, it means that there is an abnormality in the ON / OFF control of the charged particle beam by the above method, and there is a large risk of erroneous irradiation if irradiation is continued. It can be said that the safety against erroneous irradiation is further improved by stopping the operation of the particle beam generator 1 and the particle beam accelerator 2 which are the main particles for sending the particle beam to the transport device.

  When power supply to the first deflection electromagnet 15 and the second deflection electromagnet 16 is stopped due to a power failure, power failure, etc., the charged particle beam that has entered the main duct 10 is branched only by the magnetic field of the deflection permanent magnet 14. 11 is led. Accordingly, even when an abnormality such as a power failure occurs, the passage of the charged particle beam to the particle beam irradiation device 3 via the trajectory branching unit 5 is prevented, and the charged particles from the particle beam irradiation device 3 are blocked. Incorrect irradiation of the beam is prevented.

  In such a particle beam irradiation system, the charged particle beam is deflected in the branching direction 21 corresponding to the particle beam blocking block 9 by stopping the excitation of each of the first deflection electromagnet 15 and the second deflection electromagnet 16, and the first deflection electromagnet 15 and Since the charged particle beam is deflected in the passing direction 24 along a predetermined path by the excitation of each of the second deflection electromagnets 16, the excitation of the deflection electromagnets is performed when an abnormality such as a power failure or a power failure occurs, for example. As a result, the traveling direction of the charged particle beam is changed, and the passage of the charged particle beam to the particle beam irradiation apparatus 3 is prevented, thereby preventing erroneous irradiation.

  Further, the direction in which the charged particle beam is deflected by the magnetic field of the deflection permanent magnet 14 and the direction in which the charged particle beam is deflected by the respective magnetic fields of the first deflection electromagnet 15 and the second deflection electromagnet 16 are opposite to each other. The deflection permanent magnet 14, the first deflection electromagnet 15 and the second deflection electromagnet 16 are arranged close to each other in the order of the charged particle beam in the order of the first deflection electromagnet 15, the deflection permanent magnet 14 and the second deflection electromagnet 16. Therefore, it is possible to reduce the amount of displacement due to deflection, there is no need to increase the main duct 10, and the total of the deflection angles of the pair of deflection electromagnets and the deflection angle of the deflection permanent magnet are substantially reduced. Since they are the same, the main duct 10 can be produced only with a straight part without a deflection part, and the production of the vacuum duct of the particle beam transport device 5 is facilitated.

  In addition, the first deflection electromagnet 15 and the second deflection electromagnet 16 are supplied with power from a common power supply, so that when power supply abnormality or the like occurs, power supply to each of the deflection electromagnets 15 and 16 is stopped. Can be performed simultaneously. That is, it is possible to prevent power supply to only one of the deflection electromagnets 15 and 16. Thereby, passage of the charged particle beam to the particle beam irradiation apparatus 3 via the trajectory branching portion 5 can be more reliably prevented.

  Further, by making each of the first deflection electromagnet 15 and the second deflection electromagnet 16 an air-core coil, the magnetic field from each electromagnetic coil can be quickly generated and extinguished, and the response of each deflection electromagnet. Can be improved. Thereby, the erroneous irradiation accompanying the responsiveness can be improved.

  Further, the particle beam detection device 27 outputs a detection signal to the control device 6 by detecting the charged particle beam deflected in the branching direction 21. The control device 6 outputs the detection signal when the irradiation stop command is output. When the time difference from the reception time exceeds a predetermined threshold value, the control of the system, that is, the control of stopping the respective operations of the particle beam generator 1 and the particle beam accelerator 2 is performed. In the case where the passage of the charged particle beam to the particle beam irradiation device 3 via the trajectory branching unit 5 is not normal, even if the charged particle beam is erroneously input to the particle beam irradiation device 3. Transport can be prevented more reliably.

  In addition, since the first deflection electromagnet 15 and the second deflection electromagnet 16 are connected in parallel to the power supply, the inductance of the power supply load can be reduced, and the magnetic field can be generated and extinguished at a higher speed. . Thereby, the erroneous irradiation accompanying the responsiveness of a deflection electromagnet can be improved.

  In the above example, each of the first deflection electromagnet 15 and the second deflection electromagnet 16 is an air-core coil without a core, but a core may be provided in the electromagnetic coil. That is, each of the first deflection electromagnet 15 and the second deflection electromagnet 16 may have a core and an electromagnetic coil provided in the core. In this case, the core is formed of a laminated iron core in which a plurality of thin plates are laminated or a nonmagnetic material. As a result, the generation of eddy currents in the core can be suppressed, and even in this case, the generation and extinction of the magnetic field by feeding the first deflection electromagnet 15 and the second deflection electromagnet 16 can be performed quickly. it can. Accordingly, the responsiveness of the deflection electromagnet is improved, and erroneous irradiation associated with the responsiveness can be improved.

  In the above example, the materials constituting the first blocking block 25 and the second blocking block 26 are different materials, but the same material may be used. This is because the radiation shielding performance associated with the shielding differs depending on the material, but in any case, it can be improved by increasing the material thickness.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing a track branching section 5 according to Embodiment 2 of the present invention. The particle beam blocking block 9 is disposed on the upstream side of the branching portion vacuum window 13 and inside the branching duct 11 in a vacuum state. The charged particle beam guided to the branch duct 11 hits the particle beam stop block 9 and stops. Other configurations are the same as those in the first embodiment.

  Thus, even if the particle beam blocking block 9 is arranged inside the branch duct 11, the charged particle beam guided to the branch duct 11 can be stopped at the particle beam blocking block 9 as in the first embodiment. it can. In this case, basically, charged particles do not permeate through the branch portion vacuum window 13, so that it is not necessary to place special restrictions on the branch portion vacuum window 13 and the flange portion for attaching it to the branch duct 11. The configuration of the partial vacuum duct 7 can be simplified. In addition, since heat is generated in the particle beam stop block 9 by incidence of the charged particle beam, it is desirable to provide a cooling device so that the particle beam stop block 9 can be cooled.

Embodiment 3 FIG.
FIG. 4 is a block diagram showing a track branching section 5 according to Embodiment 3 of the present invention. The deflecting device 8 is charged with the first and second deflection permanent magnets 31 and 32 (a pair of deflection permanent magnets) that constantly generate a magnetic field for deflecting the charged particle beam and only when receiving power. And a deflection electromagnet 33 that generates a magnetic field for deflecting the magnetic field. The first deflection permanent magnet 31, the second deflection permanent magnet 32, and the deflection electromagnet 33 are the first deflection permanent magnet (one deflection permanent magnet) 31, the deflection electromagnet 33, and the second deflection permanent magnet in the traveling direction of the charged particle beam. (The other deflection permanent magnet) 32 are arranged in this order. The configuration of the deflection electromagnet 33 is the same as the configuration of the first deflection electromagnet 15 and the second deflection electromagnet 16 of the first embodiment.

  The branch portion vacuum duct 7 of the particle beam transport device 4 has a main duct 34 that communicates between the upstream and downstream vacuum ducts. The main duct 34 is disposed along a predetermined path along which the charged particle beam is transported. At both ends of the main duct 34, flanges 12 connected to the respective vacuum ducts are provided.

  The particle beam blocking block 9 is disposed in the main duct 34 and is disposed downstream of the deflecting device 8 at a position where the particle beam transport trajectory to the particle beam irradiation device 3 is not blocked. The particle beam blocking block 9 includes a first blocking block 25 and a second blocking block 26 disposed on the downstream side of the first blocking block 25. The materials constituting the first blocking block 25 and the second blocking block 26 are the same as those in the first embodiment.

  The direction 35 of the magnetic field by the first deflection permanent magnet 31 (in FIG. 4, the direction going from the front side to the back side of the paper) and the direction 36 of the magnetic field by the second deflection permanent magnet 32 are the same direction. The direction 37 of the magnetic field by the deflection electromagnet 33 (in FIG. 4, the direction going from the back side to the front side in the drawing) is the direction 35 of the magnetic field by the first deflection permanent magnet 31 and the direction 36 of the magnetic field by the second deflection permanent magnet 32. On the other hand, it is the opposite direction. That is, the direction in which the charged particle beam is deflected by the respective magnetic fields of the first deflection permanent magnet 31 and the second deflection permanent magnet 32 is opposite to the direction in which the charged particle beam is deflected by the magnetic field of the deflection electromagnet 33. . The feeding to the deflection electromagnet 33 is stopped when the orbital branching unit 5 receives the irradiation stop command, and is started when the orbital branching unit 5 releases the irradiation stop command.

  When the power supply to the deflection electromagnet 33 is stopped, the generation of the magnetic field of the deflection electromagnet 33 is stopped, and only the respective magnetic fields of the first deflection permanent magnet 31 and the second deflection permanent magnet 32 are generated in the main duct 34. ing. The charged particle beam passes through the magnetic field of the first deflection permanent magnet 31 and the magnetic field of the second deflection permanent magnet 32 in this order. As a result, the charged particle beam is deflected in the order of the direction 38 and the direction 39 from the direction (pre-deflection direction) 20 along the main duct 10. That is, when the charged particle beam passes through the deflecting device 8 while the power supply to the deflection electromagnet 33 is stopped, the charged particle beam travels from the pre-deflection direction 20 to the branch direction 39 that proceeds toward the particle beam blocking block 9. Deflected. As a result, the direction of the charged particle beam deviates from the trajectory to the particle beam irradiation apparatus 3, and the charged particle beam is not transported to the particle beam irradiation apparatus. The charged particle beam deviating from the trajectory to the particle beam irradiation apparatus 3 is normally blocked by disposing the particle beam blocking block 9 on the extended line in the direction 39 so that the influence of the charged particle beam on the subsequent stage can be ignored. Yes.

  When power is supplied to the deflection electromagnet 33, the magnetic fields of the first deflection permanent magnet 31, the second deflection permanent magnet 32, and the deflection electromagnet 33 are generated in the main duct 34. At this time, the charged particle beam passes through the magnetic field of the first deflection permanent magnet 31, the magnetic field of the deflection electromagnet 33, and the magnetic field of the second deflection permanent magnet 32 in this order. Thereby, the direction of the charged particle beam is deflected in the order of the direction 40, the direction 41, and the direction (passing direction) 42 from the pre-deflection direction 20. That is, when the charged particle beam passes through the deflecting device 8 while power is supplied to the deflection electromagnet 33, the direction of the charged particle beam deviates from the pre-deflection direction 20 from the particle beam blocking block 9, and a predetermined path. Is deflected in the passing direction 42. By setting the direction of the charged particle beam to the passing direction 42, the charged particle beam passes through the main duct 34 and gets on the trajectory to the particle beam irradiation apparatus 3. Other configurations are the same as those in the first embodiment.

  Thus, the direction in which the charged particle beam is deflected by the magnetic field in each of the first deflection permanent magnet 31 and the second deflection permanent magnet 32 is opposite to the direction in which the charged particle beam is deflected by the magnetic field of the deflection electromagnet 33. The first deflection permanent magnet 31, the second deflection permanent magnet 32, and the deflection electromagnet 33 are in the direction of the charged particle beam, and the first deflection permanent magnet 31, the deflection electromagnet 33, and the second deflection permanent magnet 32 are in the direction of travel. For example, when an abnormality such as a power failure or a power failure occurs, the particle beam blocking block 9 is charged by the respective magnetic fields of the first deflection permanent magnet 31 and the second deflection permanent magnet 32. A particle beam can be guided. In addition, since the direction of the charged particle beam after passing through the deflecting device 8 can be brought close to the pre-deflection direction 20, the main duct 34 can be produced only with a straight portion without a deflecting portion, and the particle beam transport device 5 The vacuum duct can be easily manufactured.

  Further, since the particle beam blocking block 9 is arranged in the main duct 34 arranged along a predetermined path, it is not necessary to provide a branch duct, and the structure of the track branching section vacuum duct 7 can be simplified. it can.

  In the above example, the length of the main duct 34 is made sufficiently long and the distance between the deflecting device 8 and the particle beam stop block 9 is increased, whereby the first deflection permanent magnet 31 and the second deflection permanent magnet. The deflection angle of the charged particle beam by the magnetic fields of the magnet 32 and the deflection electromagnet 33 can be reduced. Therefore, if it does in this way, the number of turns of the electromagnetic coil of the electromagnet 33 can be decreased, and the operation | movement of the deflection | deviation apparatus 8 can also be made faster.

  In the first and second embodiments, the deflection apparatus 8 is configured by arranging two deflection electromagnets and one deflection permanent magnet in the order of the deflection electromagnet, the deflection permanent magnet, and the deflection electromagnet. Is not limited to this. The deflection electromagnet, the deflection electromagnet, and the deflection permanent magnet may be arranged in this order, or the deflection permanent magnet, the deflection electromagnet, and the deflection electromagnet may be arranged in this order. In the case of the magnet arrangement of the deflecting device 8 of the first and second embodiments, the deflection direction of the deflection electromagnet is the same direction, and only the deflection direction of the deflection permanent magnet is the reverse direction. However, when the deflection electromagnets are arranged continuously, the deflection electromagnets reverse their deflection directions, the deflection permanent magnet deflection direction is the same as the deflection direction of the first or third deflection electromagnet, and the deflection angle is adjusted. By doing so, the incident direction of the particle beam to the deflecting device 8 and the exit direction from the deflecting device 8 can be made the same while the deflecting electromagnet is excited, and the exit is the same when the deflecting electromagnet is not energized. You can change the direction. Thereby, an effect equivalent to the effect described in the first and second embodiments can be obtained. However, since the deflection direction of the deflecting electromagnet is reversed, it is necessary to reverse the winding direction of the exciting coil constituting the electromagnet in order to share the power supply device.

The above situation also applies to the deflection device 8 described in the third embodiment.
That is, in the third embodiment, an example in which the deflection device 8 is configured by arranging two deflection permanent magnets and one deflection electromagnet in the order of a deflection permanent magnet, a deflection electromagnet, and a deflection permanent magnet is shown. The deflection permanent magnet and the deflection electromagnet may be arranged in this order, or the deflection electromagnet, the deflection permanent magnet, and the deflection permanent magnet may be arranged in this order. In this case, the deflection permanent magnets reverse the deflection direction, the deflection electromagnet deflection direction is the same as the deflection direction of the first or third deflection permanent magnet, and the deflection electromagnet is excited by adjusting the deflection angle. In this state, the incident direction of the particle beam to the deflecting device 8 and the exit direction from the deflecting device 8 can be made the same, and the exit direction can be changed when the deflection electromagnet is not excited. Thereby, an effect equivalent to the effect described in the first and second embodiments can be obtained.

Even if the configuration of the deflecting magnet of the deflecting device 8 described in this embodiment is replaced with the configuration of the deflecting magnet of the deflecting device 8 described in the first or second embodiment, the same effect can be obtained.
Furthermore, if the main duct described in this embodiment is replaced with the branching vacuum duct 7 having the branching duct described in the first or second embodiment, and conversely, the branching section vacuum in the first or second embodiment is used. Even if the duct 7 is replaced with the branching vacuum duct 7 composed of only the main duct described in the present embodiment, the ON / OFF control of the particle beam can be safely performed, and the effects of the present invention described so far The same effect can be achieved.

  In each of the above embodiments, an irradiation stop command is output from the control device 6 to the orbit branching unit 5 when the irradiation amount of the charged particle beam reaches a set amount. You may make it send an irradiation stop instruction | command directly to the orbital branch part 5 from the monitor apparatus of the particle beam irradiation apparatus 3 which detects irradiation amount.

  In each of the above embodiments, the control device 6 uses a high-speed semiconductor element (for example, an IGBT (Insulated Gate Bipolar Transistor) or the like) in order to control power supply to the first deflection electromagnet 15 and the second deflection electromagnet 16. It is desirable to have. In this way, it is possible to execute and stop power feeding to the first deflection electromagnet 15 and the second deflection electromagnet 16 at a high speed by the high-speed semiconductor element.

  In each of the above embodiments, the control device 6 controls power feeding to the deflection electromagnet based on information from a current detector (electromagnet detection means) that detects the current value of the deflection electromagnet. Also good. In this case, the control device 6 controls power feeding to the deflection electromagnet by comparing the output from the current detector (detected current value) with a preset reference value (set current value). Specifically, the control device 6 performs control to continue power supply to the deflecting electromagnet when the difference between the detected current value and the set current value is smaller than a predetermined threshold value. When the difference exceeds a predetermined threshold, control is performed to stop power feeding to the bending electromagnet. In this way, for example, when the current value of the deflecting electromagnet becomes abnormally small and an abnormality of the deflecting device 8 occurs, the irradiation of the charged particle beam from the particle beam irradiation device 3 can be stopped more reliably. it can.

  In each of the above embodiments, the control device 6 controls power feeding to the deflection electromagnet based on information from a magnetic field detector (electromagnet detection means) that detects the magnitude of the magnetic field generated by the deflection electromagnet. It may be. In this case, the magnetic field detector is inserted into the gap between the deflection electromagnet and the main duct. The control device 6 controls power feeding to the deflection electromagnet by comparing the output from the magnetic field detector (detected magnetic flux value) with a preset reference value (set magnetic flux value). Specifically, the control device 6 performs control to continue power supply to the deflection electromagnet when the difference between the detected magnetic flux value and the set magnetic flux value is smaller than a predetermined threshold value, When the difference exceeds a predetermined threshold, control is performed to stop power feeding to the bending electromagnet. Even in this case, when the abnormality of the deflecting device 8 occurs, the irradiation of the charged particle beam from the particle beam irradiation device 3 can be stopped more reliably.

  Further, in each of the above embodiments, the particle beam transport device 4 has the deflecting electromagnet and the quadrupole electromagnet other than the deflecting electromagnet included in the deflecting device 8 of the orbital branching section 5, but the present invention is not limited to this. Absent. For example, when the vacuum duct is a straight line or when the transport length is short, a deflection electromagnet or a quadrupole electromagnet other than the deflection electromagnet included in the deflection device 8 may not be provided. The presence or absence of a deflecting electromagnet other than the deflecting electromagnet included in the deflecting device 8 and a quadrupole electromagnet is determined according to the position of the particle beam irradiation device 3 with respect to the particle beam accelerating device 2.

  Further, in each of the above embodiments, the present invention is applied to a particle beam therapy system that irradiates and treats an affected part of a patient with a charged particle beam. However, the present invention is not limited to the particle beam therapy system and is widely used. The present invention may be applied to a particle beam irradiation system that irradiates a charged particle beam.

  In this case, since the equipment provided in the particle beam irradiation apparatus 3 differs depending on the application of the particle beam irradiation system, the configuration of the particle beam irradiation apparatus 3 is not limited to the above configuration. For example, when the particle beam irradiation system is used for treatment, as shown in each of the above embodiments, the particle beam irradiation apparatus 3 includes a range shifter, a beam convergence function, a beam scanning means, and the like in the case of spot scanning irradiation. In the case of large area irradiation, it often has a range shifter, scattering / diverging function, multileaf collimator, etc., but when performing large area irradiation for modification or spot scanning irradiation for analysis The range shifter may not be provided. Moreover, when performing large area irradiation, a charged particle beam may be irradiated as it is, without adjusting a characteristic.

  In each of the above embodiments, since the irradiation target is the affected area of the patient, the installation environment of the irradiation target is in the atmosphere. However, in the case of a general particle beam irradiation system, the installation environment of the irradiation target is Is not limited to the atmosphere. For example, it may be in the air, in a vacuum, or in another gas atmosphere. Further, the irradiation target may be the gas itself. Therefore, the irradiation target may be arranged in a vacuum in the particle beam irradiation apparatus 3 or the irradiation target may be arranged in a gas atmosphere other than the atmosphere outside the particle beam irradiation apparatus 3. When the irradiation target is arranged outside the particle beam irradiation apparatus 3, the charged particle beam is emitted outside the particle beam irradiation apparatus 3 through the irradiation vacuum window.

It is a block diagram which shows the particle beam therapy system by Embodiment 1 of this invention. It is a block diagram which shows the particle beam interrupting device of FIG. It is a block diagram which shows the particle beam interrupting device by Embodiment 2 of this invention. It is a block diagram which shows the particle beam interrupting device by Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Particle beam generator, 2 Particle beam accelerator, 3 Particle beam irradiation apparatus, 5 Orbit branching part, 6 Control apparatus, 8 Deflection apparatus, 9 Particle beam interruption | blocking block, 14 Deflection permanent magnet, 15 1st deflection electromagnet, 16 1st 2 deflection electromagnets, 27 particle beam detector.

Claims (10)

A particle beam generator for generating charged particle beams,
A particle beam accelerator for accelerating the charged particle beam,
The accelerated charged particle beam is provided with a duct through which the accelerated charged particle beam travels, the transport device that transports the accelerated charged particle beam to a predetermined position, and the characteristics of the charged particle beam that has been transported are adjusted to be irradiated Particle beam irradiation device for irradiating
With
The transport device has a trajectory branching unit including a deflection device composed of a deflection permanent magnet and a deflection electromagnet, and a power supply device for supplying power to an electromagnetic coil constituting the deflection electromagnet for exciting the deflection electromagnet,
When the deflection electromagnet is excited, the charged particle trajectory being transported is placed on the trajectory where the charged particle is transported to the position where the particle beam irradiation device is installed,
When the deflection electromagnet is not excited, the trajectory of the charged particles being transported is branched into a trajectory different from the trajectory where the charged particles are transported to the position where the particle beam irradiation device is installed. The particle beam irradiation system.   The particle beam irradiation system according to claim 1, further comprising a particle beam blocking block that blocks charged particles on a trajectory where charged particles branch when the deflection electromagnet is not excited. The deflection electromagnet included in the deflection device is a pair of deflection electromagnets,
The direction in which the charged particle beam is deflected by the magnetic field of the deflection permanent magnet and the direction of deflection by the magnetic field of the deflection electromagnet are opposite to each other.
The deflection permanent magnet and the deflection electromagnet are arranged in the order of one of the deflection electromagnet, the deflection permanent magnet, and the other of the deflection electromagnets in the traveling direction of the charged particle beam. The particle beam irradiation system according to claim 2.   The particle beam irradiation system according to claim 3, wherein the power supply device is a common power supply device for the pair of deflection electromagnets. The deflection permanent magnet included in the deflection device is a pair of deflection permanent magnets,
The direction in which the charged particle beam is deflected by the magnetic field of the deflection permanent magnet and the direction of deflection by the magnetic field of the deflection electromagnet are opposite to each other.
The deflection permanent magnets and the deflection electromagnets are arranged in the order of one deflection permanent magnet, the deflection electromagnet, and the other deflection permanent magnet in the traveling direction of the charged particle beam. The particle beam irradiation system according to claim 1 or 2.   The particle beam irradiation system according to any one of claims 1 to 5, wherein the electromagnetic coil is an air-core coil. The deflection electromagnet has a laminated iron core in which a plurality of thin plates are laminated,
The particle beam irradiation system according to any one of claims 1 to 5, wherein the electromagnetic coil is provided on the laminated iron core. Electromagnet detection means for detecting at least one of a current value to the electromagnetic coil and a magnitude of a magnetic field by the deflection electromagnet;
2. The apparatus according to claim 1, further comprising: a control device that controls power supply from the power supply device to the electromagnetic coil by comparing an output of the electromagnet detection means with a preset reference value set in advance. The particle beam irradiation system according to claim 1. A particle beam detector that outputs a detection signal by detecting the branched charged particle beam; and
A control device for performing control to stop the operation of the system when a time difference between the output of the irradiation stop command for stopping the power supply to the electromagnet and the reception of the detection signal exceeds a predetermined threshold; The particle beam irradiation system according to any one of claims 1 to 8, wherein the particle beam irradiation system is provided.   The particle beam irradiation system according to any one of claims 1 to 9, wherein a duct disposed in the deflecting device among the ducts of the transport device is made of a non-conductive material. .

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