JP5409521B2 - Particle beam therapy system - Google Patents

Description

  The present invention relates to a particle beam treatment apparatus for treating a tumor such as cancer by irradiation with a heavy ion beam such as a proton beam or a carbon ion beam.

  As one of the cancer treatment methods, particle beam therapy is known in which an affected area is irradiated with an ion beam such as protons or carbon ions. When ions such as protons and carbon ions are incident on a material with high energy, a lot of energy is lost at the end of the range. In particle beam therapy, this property is used to irradiate the patient with an ion beam so that cancer cells lose a lot of energy. Then, cancer cells can be destroyed without damaging surrounding healthy tissues. In particle beam therapy, the spatial spread and energy of the ion beam are adjusted to form a dose distribution that matches the shape of the affected area.

  The particle beam therapy system used for the particle beam therapy includes an ion source, an accelerator for accelerating ions generated from the ion source, a beam transport device for transporting an ion beam emitted from the accelerator, and an irradiation for irradiating the affected part with a beam with a desired dose distribution. It consists of a device.

  Examples of the accelerator used in the particle beam therapy system include a synchrotron and a cyclotron. Both accelerators share the function of accelerating the incident ions to a predetermined energy and emitting them as ion beams.

  The ion beam emitted from the accelerator is transported to the irradiation device by the beam transport device. The beam transport device is equipped with a deflection electromagnet that greatly changes the traveling direction of the ion beam, a steering electromagnet that finely adjusts the traveling direction of the beam, and a quadrupole electromagnet that focuses and diverges the ion beam. By appropriately adjusting the amount of excitation, a beam of an appropriate size and position is transported to the irradiation device.

  In order to irradiate the affected part with a beam from a plurality of directions, a beam transport device and an irradiation device may be installed in the rotating gantry. The beam transport device of the particle beam therapy system having a rotating gantry can be roughly divided into a rotating beam transport device installed in the rotating gantry and a fixed beam transport device installed and fixed in the building.

  In the beam transport apparatus, optical parameters of the beam called “Twiss parameter” and “dispersion function” are adjusted. The Twiss parameter to be adjusted has two types of α and β in two directions orthogonal to each other in a plane perpendicular to the traveling direction of the beam. Normally, αx, βx, αy, βy are selected as adjustment parameters, where x is the horizontal direction and y is the vertical direction. β is a parameter representing the size of the spatial distribution of the beam, and α represents the rate of change of β with respect to the beam traveling direction. The dispersion function is an index indicating the correlation between the energy variation of each ion particle constituting the beam and the position and the inclination of the trajectory. In a normal transport system, the horizontal dispersion function is adjusted. These are expressed as ηx and η′x, respectively. The dispersion functions ηx and η′x are generated when they pass through the deflection electromagnet in a state of 0. In addition, when it passes through the bending electromagnet with a specific dispersion function value, it has a property of becoming 0 after the passage. Further, when ηx and η′x are both 0, if they are incident on a linear beam transport device composed of a quadrupole electromagnet and a drift space, ηx and η′x are zero throughout the linear beam transport device. It remains. In general, it is necessary to reduce the spatial spread of the beam in the irradiation apparatus. Since the spread of the beam increases as the absolute value of the dispersion function increases, in the irradiation apparatus, when the beam size is reduced, the dispersion functions ηx and η′x are set to 0, β is further reduced, and α is set to 0. To. Further, in order to transport the beam to the irradiation point without loss, it is necessary to make the beam size smaller than the magnetic pole gap of the electromagnet when passing through the deflecting electromagnet or the quadrupole electromagnet in the beam transport apparatus.

  When the irradiation device is installed in the rotating gantry, the beam is transported with the same excitation amount of the quadrupole electromagnet at all irradiation angles so that the re-excitation of the electromagnet is not required when the irradiation direction is changed. More specifically, the quadrupole electromagnet is adjusted so that the beam's Swiss parameter has the same value in the horizontal and vertical directions at the boundary between the rotating beam transport device installed in the rotating gantry and the fixed beam transport device fixed in the building. ing. Then, the Swiss parameter at the irradiation point becomes constant regardless of the irradiation direction.

  Further, in the beam transport device, it is necessary to adjust the beam irradiation position and the beam trajectory gradient. The beam position and the gradient of the trajectory are adjusted by an electromagnet called a steering electromagnet in the beam transport device. The horizontal position is x, the orbital gradient is x ', the vertical position is y, and the orbital gradient is y'. In order to adjust these four parameters, two or more horizontal steering electromagnets and two or more vertical steering electromagnets are required.

  In addition, a high-speed kicker may be installed in the beam transport device for beam irradiation control. A high-speed kicker uses an electromagnet that rises quickly. When the high-speed kicker excites the magnetic field, the kicked beam deviates from the trajectory and collides with the downstream beam damper. This controls the beam irradiation and stoppage. In this case, it is necessary to take a distance of about several meters between the kicker and the damper. As a technique for shortening the beam transport path with this system, Patent Document 1 is cited.

  In the irradiation apparatus, an ion beam irradiation field is formed in accordance with the shape of the affected part. Irradiation field formation is realized by controlling the ion beam energy in the depth direction of the affected area and forming a beam shape that matches the shape of the affected area with a collimator or the like. The irradiation field formation method in the irradiation device includes a scatterer irradiation method that spreads the beam transported from the transport device by a scatterer, and a scanning irradiation method that scans the transported thin beam according to the shape of the affected area by a scanning magnet. There is.

  In the scatterer irradiation method, the irradiator is provided with a scatterer that spreads the ion beam into the shape of the affected part, and a range modulation unit that controls the range of the ion beam according to the depth of the affected part from the body surface. As an example of the scatterer irradiation method, a method using a rotary range modulator will be described. In this method, a second scatterer that is a concentric combination of a range modulator in the form of a propeller that rotates about an axis parallel to the traveling direction of the beam and a metal having a different density in a concentric circle in the irradiation device. It is installed from the upstream of the route. The rotary range modulator always rotates during beam irradiation. Further, the thickness of the rotary range modulator changes with respect to the circumferential direction of rotation. Therefore, the energy lost by the beam can be controlled according to the timing at which the beam passes through the rotary range modulator, and thus the range of the ion beam can be controlled. By using this principle, it is possible to control the ion beam extraction timing from the accelerator and form a beam energy distribution that matches the shape of the affected area to be irradiated.

  The spot scanning irradiation method will be described as an example of the scanning irradiation method. The scanning irradiation method irradiation apparatus is provided with two scanning electromagnets for scanning the beam. With these scanning electromagnets, the beam is scanned in the irradiation device in a plane perpendicular to the traveling direction of the beam so that only the affected part is irradiated with the beam. In addition, in order to form an irradiation field that matches the shape of the affected area, the energy of the beam emitted from the accelerator is changed, or the thickness of the energy absorber disposed in the beam transport device is changed, so that it is transported to the irradiation device. Change the energy of the emitted beam. Then, the position of the Bragg peak changes depending on the energy of the beam, and an irradiation field matching the shape of the affected part can be formed. A more detailed description of these irradiation methods is detailed in Non-Patent Document 1.

JP 2009-279045 A

Alfred Smith et al. "The M. D. Anderson proton therapy system" Medical Physics 36 (9), September 2009

  As described above, in the conventional beam transport device in the particle beam therapy system, the six parameters αx, βx, αy, βy, ηx, and η′x are adjusted by the quadrupole electromagnet. Further, the four parameters of the beam position and the orbital gradient x, x ′, y, y ′ are adjusted by the steering electromagnet. Therefore, the beam transport device requires at least one deflection electromagnet and six quadrupole electromagnets, and two steering electromagnets each for horizontal trajectory adjustment and vertical trajectory adjustment. To adjust each parameter with a limited excitation current with an electromagnet, it is necessary to increase the beam trajectory length downstream of the electromagnet, and to realize a small beam transport device, it is essential to increase the electromagnet power supply capacity, The cost was high.

  In the particle beam therapy system according to the present invention, the fixed beam transport device has one deflection electromagnet, and has two linear portions divided by the deflection electromagnet. Three quadrupole electromagnets are arranged in the first linear beam transport device positioned upstream of the deflecting electromagnet in the beam traveling direction of the charged particle beam, and the charged particle beam downstream of the deflecting electromagnet in the traveling direction. Four quadrupole electromagnets are arranged in the second linear beam transport device located on the side.

  ADVANTAGE OF THE INVENTION According to this invention, the beam transport apparatus with a shorter transport path than before can be implement | achieved, and a small particle beam therapy apparatus can be provided.

1 is an overall configuration diagram of a particle beam therapy system according to a first embodiment of the present invention. It is a whole block diagram of the particle beam therapy apparatus of the 2nd Embodiment of this invention. It is a whole block diagram of the particle beam therapy apparatus of the 3rd Embodiment of this invention. It is a whole block diagram of the particle beam therapy apparatus of the 4th Embodiment of this invention.

(First embodiment)
The first embodiment of the present invention will be described below with reference to the drawings.

  A first embodiment of the present invention is shown in FIG. FIG. 1 shows the overall configuration of a particle beam therapy system 100 according to this embodiment. The particle beam therapy system 100 includes a front stage accelerator 200, a synchrotron 300, a beam transport device, and a rotating gantry 500.

  The beam transport device includes a fixed beam transport device 400 fixed to the building of the particle beam therapy system 100 and a rotating beam transport device 510 connected to the fixed beam transport device 400 and configured to be rotatable. A fixed beam transport device 400 is positioned upstream with respect to the traveling direction of a charged particle beam (hereinafter referred to as a beam), and a rotating beam transport device 510 is positioned downstream. A rotating beam transport device 510 and an irradiation device 520 are connected to the rotating gantry 500. The rotating beam transport device 510 and the fixed beam transport device 400 are connected at a connection point 530. The rotating gantry 500 rotates around the connection point 530 around the rotation axis direction 540 of the second linear portion 420 of the fixed beam transport device 400. By rotating the rotating gantry 500, the irradiation direction of the beam to the affected area at the irradiation point 550 can be adjusted. In addition, a power source 600 is connected to each device installed in the synchrotron 300, the fixed beam transport device 400, and the rotating beam transport device 510, and the power source 600 is based on a command from the controller terminal 800 through the control device 700. Be controlled. The power source 600 includes an extraction high-frequency power source 610, a deflecting electromagnet power source 620, a quadrupole electromagnet power source 630, a steering electromagnet power source 640, a high-speed kicker power source 650, and an exit septum electromagnet 660. Based on the command signal from the coordinator terminal 800, the control device 700 controls the power supply 600 to control each device constituting the synchrotron 300, the rotating beam transport device 400, and the rotating beam transport device 510.

  In the present particle beam therapy system, the beam preliminarily accelerated by the former accelerator 200, which is a linac, is accelerated to the energy specified by the synchrotron 300. The accelerated beam is emitted to the fixed beam transport device 400 through the extraction septum electromagnet 310. The fixed beam transport device 400 transports the beam to the connection point 530 and then enters the rotating beam transport device 510. Finally, the beam passes through the irradiation device 520 and is transported to the irradiation point 550 with a desired beam size and beam position.

The synchrotron 300 includes an incident septum electromagnet 320 that is used when a beam is incident, a deflection electromagnet 330 that deflects the beam trajectory, a high-frequency acceleration cavity 340 that accelerates the beam, a quadrupole electromagnet 350 that circulates the beam stably, and beam emission. A hexapole electromagnet 360 that is excited to narrow the stable region sometimes, a high-frequency electrode 370 that kicks the circulating beam out of the stable region, and a septum electromagnet 310 that guides the outgoing beam to the fixed beam transport device 400 are installed. . During acceleration, the beam circulates inside the synchrotron 300. A high frequency electric field matched to the frequency that the beam orbits is excited in the high frequency acceleration cavity 340. When the beam goes around the synchrotron 300, the beam is accelerated by the high-frequency electric field. During acceleration, the magnetic field of the deflecting electromagnet 330 of the synchrotron 300 is increased in accordance with the beam energy so that the beam trajectory becomes constant. In addition, as the beam accelerates, the time required to circulate the synchrotron 300 is shortened, so that the frequency of the high-frequency electric field excited in the high-frequency acceleration cavity 340 is increased. When the beam is accelerated to the specified energy, the frequency of the high frequency electric field excited in the high frequency acceleration cavity 340 and the magnetic field of the deflection electromagnet 330 are kept constant.
From this state, the hexapole electromagnet 360 is excited to excite a high frequency electric field on the high frequency electrode 370 for emission. When the hexapole electromagnet 360 is excited, depending on the horizontal position and gradient displacement of the particles constituting the beam, it does not circulate stably within the synchrotron 300 and reaches the position of the exiting septum electromagnet 310. The particles that stably circulate also increase in the horizontal position and gradient displacement over time due to the kick from the high-frequency electric field generated in the extraction high-frequency electrode 370, and cannot stably circulate and reach the extraction septum electromagnet 310. When the beam is extracted from the synchrotron 300 by this method, the emission and stop of the beam can be controlled by ON / OFF control of the high frequency power supply 610 for supplying power.

  One fixed electromagnet 430 is installed in the fixed beam transport device 400. By this deflection electromagnet 430, the fixed beam transport device 400 is divided into two linear beam transport devices. The fixed beam transport device 400 includes a first linear beam transport device (first linear portion) 410 positioned upstream of the deflection electromagnet 430 in the beam traveling direction and a downstream position of the deflection electromagnet 430 in the beam traveling direction. A second linear beam transport device (second linear portion) 420 is provided. One of the first straight portions 410 is connected to the outgoing septum electromagnet 310, and the other is connected to the second straight portion 420. One of the second straight portions 420 is connected to the first straight portion 410 and the other is connected to the rotating beam transport device 510. In the first straight portion 410, three quadrupole electromagnets 441 to 443, one profile monitor 451, two steering electromagnets 461, 462, and a high-speed kicker 470 are arranged. A steering electromagnet 461, a quadrupole electromagnet 441, a quadrupole electromagnet 442, a steering electromagnet 462, a high-speed kicker electromagnet 470, a quadrupole electromagnet 443, and a profile monitor 451 are arranged on the beam trajectory of the first straight portion 410 in order from the upstream side in the beam traveling direction. The In the second linear portion 420, four quadrupole electromagnets 444 to 447, two profile monitors 452, 453, and one steering electromagnet 463 are arranged. A steering electromagnet 463, a quadrupole electromagnet 444, a quadrupole electromagnet 445, a quadrupole electromagnet 447, a quadrupole electromagnet 446, a profile monitor 453, and a profile monitor 452 are arranged on the beam trajectory of the second linear portion 420 in order from the upstream side in the beam traveling direction. The The deflection electromagnet 430 is provided with a damper 480, and the beam kicked by the high speed kicker 470 collides with the damper 480 and is blocked.

  The deflection electromagnet 430 is supplied with a current from the deflection electromagnet power source 620. Similarly, each of the quadrupole electromagnets 441 to 447, the steering electromagnets 461 to 463, and the high speed kicker 470 are supplied with current from the quadrupole electromagnet power source 630, the steering electromagnet power source 640, and the high speed kicker power source 650, respectively. These power supplies 610, 620, 630, and 640 are controlled in output current by the control device 700. The exciting currents of the respective electromagnets can be individually set according to the instructions of the adjuster through the adjuster terminal 800.

  The profile monitors 451 to 453 are charged particle beam measuring apparatuses that measure the beam position and beam size using a multi-wire drift chamber. The profile monitors 451 to 453 can measure the horizontal and vertical distributions of the beams passing therethrough. The output signals of the profile monitors 451 to 453 are processed by the profile monitor signal processing device 710, and the beam size and beam position are calculated. Thereafter, the beam size and beam position results are displayed on the adjuster terminal 800 through the control device 700.

  The steering electromagnets 461 to 463 can excite a magnetic field independently in the vertical direction and the horizontal direction. Therefore, it is possible to deflect the beam independently in the horizontal and vertical directions with one electromagnet.

  The rotating beam transport device 510 is provided with three deflection electromagnets and six quadrupole electromagnets, and each electromagnet is supplied with an excitation current from a power source (not shown) in the same manner as the electromagnets installed in the fixed beam transport device 400. The Further, a profile monitor (not shown) is installed in the rotating beam transport apparatus 510, and the beam size can be measured like the profile monitors 451 to 453 of the fixed beam transport apparatus 400.

  The irradiation apparatus 520 of the present embodiment is an irradiation apparatus corresponding to the scanning irradiation method, and is provided with a scanning electromagnet (not shown) and a profile monitor (not shown) for scanning the beam. Next, a method for adjusting the excitation amounts of the quadrupole electromagnets 441 to 447 and the steering electromagnets 461 to 463 installed in the fixed beam transport apparatus 400 will be described.

  By adjusting the fixed beam transport device 400, the traveling direction of the beam coincides with the rotational axis of the rotating gantry 500 at the connection point 530, and the beam's Twis parameter is set to a predetermined target value (for example, αx = αy = 0, βx = βy = 6 m).

  First, the parameters of the beam emitted from the emission septum electromagnet 310 are measured. The Twiss parameter and emittance are measured by a technique called the Q-scan method. The amount of excitation of the steering electromagnets 461 and 462 of the first linear portion 410 is adjusted so that the center trajectory of the beam matches the design trajectory of the deflection electromagnet 430. Next, the quadrupole electromagnets 441 to 443 are changed within a predetermined excitation amount range, and the beam size change in the profile monitor 451 is measured. From the amount of excitation of each of the quadrupole electromagnets 441 to 443 and the behavior of the beam size in the profile monitor 451, the Twiss parameter and emittance in the extraction septum electromagnet 310 can be measured. The dispersion function can be measured by changing the energy of the beam emitted from the synchrotron 300 minutely and changing the position on the profile monitor 451 according to the energy change. Also here, the amount of excitation of each of the quadrupole electromagnets 441 to 443 of the first linear portion 410 is changed within a predetermined range, and the beam position on the profile monitor is measured. From the behavior of the position change accompanying the energy change, the dispersion function in the extraction septum electromagnet 310 can be obtained.

From the above measurement, it is possible to determine the amount of excitation of the quadrupole electromagnet that can set the dispersion functions ηx and η′x to 0 at the exit of the deflection electromagnet 430, that is, the second linear portion 420, and can pass through the deflection electromagnet 430 without loss of beam. . Further, from the measurement results of the two profile monitors 452 and 453 installed in the second linear portion 420 by the steering electromagnets 462 and 463 of the fixed beam transport apparatus 400, the direction 540 of the rotation axis of the rotating gantry 500 and the traveling direction of the beam are determined. Match. In addition, the amount of excitation of the quadrupole electromagnets 444 to 447 of the second linear portion 420 that matches the Swiss parameter at the connection point 530 with the target value can be obtained from the measurement result of the Twiss parameter. The adjustment of the quadrupole electromagnets 441 to 447 and the steering electromagnets 461 to 463 of the fixed beam transport apparatus 400 is completed by the above procedure.

  In the beam transport apparatus of this embodiment, a quadrupole electromagnet 443 and a deflection electromagnet 430 are disposed between the steering electromagnets 462 and 463. The quadrupole electromagnet 443 is an electromagnet that diverges in the horizontal direction and converges in the vertical direction with respect to the beam. The deflecting electromagnet 430 has a magnetic pole end face at a certain angle from the perpendicular to the beam traveling direction. Then, the deflecting electromagnet 430 does not converge or diverge in the horizontal direction of the beam, but provides a convergence effect in the vertical direction. A device having a convergence / divergence action is arranged between the steering electromagnets 462 and 463 as in the present embodiment, and the arrangement of the quadrupole electromagnets after the steering electromagnet 463 is set to the arrangement shown in the present embodiment. The vectors formed by the orbital displacement and the gradient displacement at the connection point 530 per unit deflection amount of 462 and 463 are orthogonal to each other. As a result, the range of trajectory deviation that can be corrected can be widened. That is, the short beam transport device as shown in the present embodiment can adjust the beam position with a small current value.

  The rotating beam transport device 510 is provided with three deflecting electromagnets and six quadrupole electromagnets. By appropriately determining the amount of excitation of the quadrupole electromagnet in the rotating beam transport device 510, both αx and αy at the irradiation point 550 are obtained. The dispersion functions ηx and η′x can be set to 0, and βx and βy can be set to predetermined values. If the Twiss parameter and beam trajectory can be adjusted at the connection point 530, the Twiss parameter and dispersion function of the beam at the irradiation point 550 can be made constant regardless of the rotation angle of the rotating gantry 500, and the beam is irradiated by changing the irradiation direction to the affected area. In this case, it is possible to irradiate the affected area under the same beam conditions without changing the excitation amounts of the quadrupole electromagnets 441 to 447 of the fixed beam transport device 400 and the quadrupole electromagnet 560 of the rotating beam transport device 510.

  Thereby, when irradiating the affected part from a plurality of directions, a particle beam therapy system with a smaller installation area can be realized while keeping the irradiation direction switching time short.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. Here, only different points from the first embodiment will be described. FIG. 2 shows the overall configuration of the particle beam therapy system 100 of this embodiment. In the second embodiment, a steering electromagnet 464 is installed in the second linear portion 420 downstream of the beam transport device in the first embodiment. In the second linear portion 420 of this embodiment, a steering electromagnet 463, a quadrupole electromagnet 444, a quadrupole electromagnet 445, a steering electromagnet 464, a quadrupole electromagnet 447, and a quadrupole electromagnet 446 are sequentially arranged from the upstream side in the beam traveling direction along the beam trajectory. A profile monitor 453 and a profile monitor 452 are arranged. The steering electromagnet 464 of this embodiment is disposed between the quadrupole electromagnet 445 and the quadrupole electromagnet 446.

  In this embodiment, adjustment of the beam trajectory at the connection point 530 is performed by the steering electromagnets 462 to 464. Two quadrupole electromagnets 444 and 445 are installed between the steering electromagnets 462 and 463, and the beam position generated at the connection point 530 per unit deflection amount in the steering electromagnet as described in the first embodiment. A vector composed of displacement and gradient displacement is in a substantially orthogonal relationship. Furthermore, since there are a quadrupole electromagnet and a deflection electromagnet between the steering electromagnet 462 and the steering electromagnet 463, the steering electromagnet 462 can be further added to the adjustment of the beam trajectory depending on the amount of excitation of the quadrupole electromagnet. Adjustable beam trajectory displacement can be widened.

(Third embodiment)
The third embodiment of the present invention will be described below with reference to the drawings. Here, only a different part from 2nd Embodiment is demonstrated. FIG. 3 shows the overall configuration of the particle beam therapy system 100 of this embodiment. Compared to the device arrangement in the second embodiment, the positions of the quadrupole electromagnet 447 and the steering electromagnet 464 are exchanged. That is, the second linear portion 420 of this embodiment includes a steering electromagnet 463, a quadrupole electromagnet 444, a quadrupole electromagnet 447, a quadrupole electromagnet 447, a steering electromagnet 464, and a quadrupole electromagnet in order from the upstream in the beam traveling direction along the beam trajectory. 446, a profile monitor 453, and a profile monitor 452 are arranged. Even with this arrangement, the effects described in the first and second embodiments can be obtained, and the beam trajectory can be adjusted in a wide range with a small amount of steering magnet excitation.

(Fourth embodiment)
The fourth embodiment of the present invention will be described below with reference to the drawings. Here, only different points from the first embodiment will be described. A fourth embodiment of the present invention is shown in FIG. FIG. 4 shows the configuration of the particle beam therapy system according to this embodiment. This apparatus includes a front stage accelerator 200, a synchrotron 300, a fixed beam transport apparatus 400, and two rotating gantry 501 to 502. Each of the rotating gantry 501 and 502 is provided with an irradiation device for irradiating an irradiation target with a beam.

  The fixed beam transport apparatus 400 is provided with deflection electromagnets (course switching electromagnets) 431 and 432 for transporting the beam to any one of the selected irradiation apparatuses. By the deflection electromagnets 431 and 432, the fixed beam transport apparatus 400 is divided into four first straight portions 411, second straight portions 412, third straight portions 421, and fourth straight portions 422. The deflection electromagnet 431 is a course switching electromagnet that is closest to the emission septum electromagnet 310 and is arranged on the most upstream side in the beam traveling direction. The first linear portion 411 is a first linear beam transport device positioned between the deflection electromagnet 431 and the emission septum electromagnet 310. A third linear portion 421, one connected to the rotating beam transport device 531 and the other connected to the deflecting electromagnet 431, and a fourth straight portion connected to the rotating transport device 532 and one connected to the deflecting electromagnet 432 Reference numeral 422 denotes a second linear beam transport device.

  The irradiation device to which the beam is transported differs depending on the excitation state of the deflection electromagnets 431 and 432. When the deflection electromagnet 431 is excited, the beam is deflected by the deflection electromagnet 431, passes through the third linear portion 421, and is transported to the irradiation point 551. On the other hand, when the deflection electromagnet 431 is not excited, the beam is transported to the second linear portion 412. In this case, the deflection electromagnet 432 is excited, and the beam transported to the second linear portion 412 is deflected by the deflection electromagnet 432, passes through the fourth linear portion 422, and is transported to the irradiation point 552.

  In the first linear portion 411, three quadrupole electromagnets 440, one profile monitor 450, two steering electromagnets 460, and a high speed kicker 470 are arranged. Three quadrupole electromagnets 440, one profile monitor 450, and two steering electromagnets 460 are arranged on the second linear portion 412. The equipment arrangement of the third linear part 421 and the fourth linear part 422 is the same, and four quadrupole electromagnets 440, two profile monitors 450, and two steering electromagnets 460 are arranged, respectively.

  By adjusting the quadrupole electromagnet 440 and the steering electromagnet 460 of the fixed beam transport apparatus 400 in the same manner as in the first embodiment, the beam traveling direction is changed at the connection points 531 and 532 to the rotating shafts 541 and 542 of the rotating gantry 501 and 502. And the dispersion functions ηx and η′x are set to 0, and the Twiss parameters of the beam are set to predetermined target values (for example, αx = αy = 0, βx = βy = 6 m). This adjustment makes the beam parameter unchanged regardless of the rotation angle of the rotating gantry 501 and 502.

  Thereby, a particle beam therapy system having a small installation area can be realized.

DESCRIPTION OF SYMBOLS 100 Particle beam therapy apparatus 200 Previous stage accelerator 300 Synchrotron 310 Outgoing septum electromagnet 320 Incident septum electromagnet 330, 430-432 Deflection electromagnet 340 High frequency acceleration cavity 350, 440-447, 560 Quadrupole electromagnet 360 Hexapole electromagnet 370 Outgoing high frequency Electrode 400 Fixed beam transport device 410, 411 First straight line part 412, 420 Second straight line part 421 Third straight line part 422 Fourth straight line part 450-453 Profile monitor 460-464 Steering electromagnet 470 High-speed kicker 480 Damper 500-502 Rotating gantry 510 Rotating beam transport device 520 Irradiation device 530-532 Connection point 540-542 Rotating shaft 550-552 Irradiation point 600 Power source 610 Ejecting high frequency power source 620 Deflection electromagnet power source 630 Quadrupole electromagnet power source 640 Steering Grayed magnet power supply 650 fast kicker power 700 controller 710 profile monitor signal processing device 800 coordinator terminal

Claims (18)

An accelerator to accelerate the charged particle beam;
An irradiation device for emitting the charged particle beam to an irradiation target;
A beam transport device that transports the charged particle beam emitted from the accelerator to the irradiation device;
The accelerator includes an exit beam deflecting device that guides the charged particle beam to the beam transport device when taking out the charged particle beam,
The beam transport device includes a fixed beam transport device fixed to a building, and a rotating beam transport device that is connected to the fixed beam transport device and rotates in accordance with an irradiation direction for irradiating the charged particle beam,
The fixed beam transport device includes a deflection electromagnet for deflecting the charged particle beam, three quadrupole electromagnets disposed in a first linear beam transport device positioned upstream of the deflection electromagnet in the beam traveling direction, Comprising four quadrupole electromagnets arranged in a second linear beam transport device located downstream of the deflection electromagnet in the beam traveling direction;
By exciting three quadrupole electromagnets arranged in the first linear beam transport device and the deflection electromagnet, the dispersion function of the charged particle beam in the second linear beam transport device is set to zero. ,
By exciting four quadrupole magnets arranged in the second linear beam transport device, the Twisted parameter of the charged particle beam at the connection point between the fixed beam transport device and the rotating beam transport device is targeted. To match the value,
A particle beam therapy system. The particle beam therapy system according to claim 1, wherein
The first linear beam transport device is connected to the exit beam deflection device of the accelerator;
The second linear beam transport device is connected to the rotating beam transport device;
The first and second linear beam transport apparatuses each include a charged particle beam measuring apparatus that measures the position and spread of the charged particle beam. The particle beam therapy system according to claim 2, wherein
Of the three quadrupole electromagnets arranged in the first linear beam transport device, two quadrupole electromagnets are quadrupole electromagnets having different polarities,
The particle beam therapy system characterized in that at least two of the four quadrupole electromagnets arranged in the second linear beam transport device are quadrupole electromagnets having different polarities. In the particle beam therapy system according to claim 3,
The first linear beam transport device includes at least one charged particle beam measurement device on the downstream side of the two quadrupole electromagnets. In the particle beam therapy system according to claim 3,
The second linear beam transport device includes at least two charged particle beam measuring devices on the downstream side of the two quadrupole electromagnets. The particle beam therapy system according to claim 4, wherein
The second linear beam transport device includes at least two charged particle beam measuring devices on the downstream side of the two quadrupole electromagnets. The particle beam therapy system according to claim 5, wherein
The fixed beam transport apparatus includes at least two beam trajectory correcting electromagnets for adjusting a beam trajectory. In the particle beam therapy system according to claim 7,
The second linear beam transport device includes at least one beam trajectory correcting electromagnet,
The beam trajectory correcting electromagnet is provided upstream of at least two charged particle beam measuring devices provided in the downstream linear beam transport device. The particle beam therapy system according to claim 8, wherein
A particle beam therapy system characterized in that the second linear beam transport device includes two beam trajectory correcting electromagnets. An accelerator to accelerate the charged particle beam;
A plurality of irradiation devices for emitting the charged particle beam to an irradiation target;
A beam transport device for transporting the charged particle beam emitted from the accelerator to any one of the irradiation devices;
The accelerator includes an exit beam deflecting device that guides the charged particle beam to the beam transport device when taking out the charged particle beam,
The beam transport device has a fixed beam transport device fixed to a building, and a plurality of rotating beam transport devices that rotate in accordance with an irradiation direction for irradiating the charged particle beam,
The fixed beam transport device includes a plurality of course switching electromagnets for transporting the charged particle beam to any one of the selected irradiation devices, the course switching electromagnet located on the most upstream side, and the beam deflection for emission. A first linear beam transport device formed between the devices, and formed downstream of the first linear beam transport device in the beam traveling direction, and connected to any one of the rotating beam transport devices. A second linear beam transport device,
The first linear beam transport device has three quadrupole electromagnets,
It said second linear beam transport device have a four quadrupole electromagnets,
By exciting three quadrupole electromagnets arranged in the first linear beam transport device and the course switching electromagnet, the dispersion function of the charged particle beam in the second linear beam transport device is set to 0. age,
By exciting four quadrupole magnets arranged in the second linear beam transport device, the Twisted parameter of the charged particle beam at the connection point between the fixed beam transport device and the rotating beam transport device is targeted. To match the value,
A particle beam therapy system. The particle beam therapy system according to claim 10, wherein
Said 1st and 2nd linear beam transport apparatus is equipped with the charged particle beam measuring apparatus which measures the position and spread of the said charged particle beam, The particle beam therapy apparatus characterized by the above-mentioned. The particle beam therapy system according to claim 11, wherein
2. The particle beam therapy system according to claim 1, wherein the linear beam transport device includes at least two quadrupole electromagnets including two quadrupole electromagnets having different polarities. The particle beam therapy system according to claim 11, wherein
Of the three quadrupole electromagnets arranged in the first linear beam transport device, two quadrupole electromagnets are quadrupole electromagnets having different polarities from each other,
A particle beam therapy system comprising at least one charged particle beam measurement device on the downstream side of two quadrupole electromagnets arranged in the first linear beam transport device. The particle beam therapy system according to claim 11, wherein
At least two of the four quadrupole electromagnets arranged in the second linear beam transport device are quadrupole electromagnets having different polarities from each other;
A particle beam therapy system comprising at least two charged particle beam measurement devices on the downstream side of the two quadrupole electromagnets arranged in the second linear beam transport device. The particle beam therapy system according to claim 13, wherein
The second linear beam transport device includes at least two charged particle beam measuring devices on the downstream side of the two quadrupole electromagnets. The particle beam therapy system according to claim 14, wherein
The particle beam therapy system according to claim 1, wherein the beam transport device includes at least two beam trajectory correction electromagnets for adjusting a beam trajectory. The particle beam therapy system according to claim 16, wherein
The second linear beam transport device includes at least one beam trajectory correcting electromagnet,
The beam trajectory correcting electromagnet is provided upstream of at least two charged particle beam measuring devices provided in the second linear beam transport device. The particle beam therapy system according to claim 17,
A particle beam therapy system characterized in that the second linear beam transport device includes two beam trajectory correcting electromagnets.

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