WO2020044604A1 - Accélérateur de faisceau de particules, et système de thérapie par faisceau de particules - Google Patents

Accélérateur de faisceau de particules, et système de thérapie par faisceau de particules Download PDF

Info

Publication number
WO2020044604A1
WO2020044604A1 PCT/JP2019/005847 JP2019005847W WO2020044604A1 WO 2020044604 A1 WO2020044604 A1 WO 2020044604A1 JP 2019005847 W JP2019005847 W JP 2019005847W WO 2020044604 A1 WO2020044604 A1 WO 2020044604A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetic field
particle beam
frequency
electric field
frequency electric
Prior art date
Application number
PCT/JP2019/005847
Other languages
English (en)
Japanese (ja)
Inventor
知新 堀
隆光 羽江
孝道 青木
孝義 関
Original Assignee
株式会社日立製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社日立製作所 filed Critical 株式会社日立製作所
Publication of WO2020044604A1 publication Critical patent/WO2020044604A1/fr

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H13/00—Magnetic resonance accelerators; Cyclotrons
    • H05H13/02—Synchrocyclotrons, i.e. frequency modulated cyclotrons
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
    • H05H7/10—Arrangements for ejecting particles from orbits

Definitions

  • the present invention relates to a particle accelerator and a particle therapy system.
  • Patent Document 1 discloses a voltage source for sweeping a high frequency voltage in a cavity to accelerate particles from a particle source which is a plasma column, and a particle source in a cavity. It is described that an accelerator is constituted by a magnet moving on an orbit, a regenerator, and a ferromagnetic device arranged in a cavity with a space from the regenerator to eliminate a magnetic field bump formed by the magnet.
  • Patent Literature 1 discloses a configuration of a particle beam accelerator called a synchrocyclotron used in a particle beam therapy system.
  • a particle beam accelerator called a synchrocyclotron is an injection device that includes an ion source, a main magnetic field magnet that generates a main magnetic field for stably circulating the beam, and an acceleration cavity that applies a high-frequency electric field to accelerate the beam in the circumferential direction
  • a gradient magnet for intentionally displacing the beam from the balanced orbit and applying a magnetic field to the beam, and an exit channel for extracting the beam displaced from the balanced orbit outside the accelerator and guiding it to a downstream beam transport system.
  • the beam incident from the ion source orbits, feeling the main magnetic field.
  • the beam is accelerated to a predetermined energy by adjusting the phase of the high-frequency electric field for acceleration so as to match the timing of the orbiting beam passing through the gap of the acceleration cavity.
  • the frequency at which the beam circulates varies depending on the energy, so that the frequency of the high-frequency electric field for acceleration needs to be modulated accordingly.
  • a gradient magnetic field including a quadrupole magnetic field and a hexapole magnetic field is applied to the beam that has reached a predetermined energy.
  • the betatron frequency in the beam orbiting plane that is, the horizontal tune is designed to be around 1 (typically 0.95 or more and less than 1). Increases, and the beam is greatly displaced from the equilibrium trajectory to reach the output channel.
  • the output channel is a magnet called a septum, and a magnetic field opposite to the main magnetic field is applied to the beam to expand the radius of curvature of the beam and completely depart the beam orbit from the equilibrium orbit.
  • the beam that has escaped from the equilibrium orbit jumps out of the accelerator and is guided to the irradiation device via the transport system. Since the energy of the beam extracted in this manner is fixed, the energy is adjusted by reducing the beam energy by passing the beam through a scatterer called a degrader at any stage up to the irradiation device.
  • the present invention includes a plurality of means for solving the above-mentioned problems.
  • a particle beam accelerator for generating a static magnetic field, a frequency modulatable and a beam acceleration
  • a first high-frequency electric field applying device that applies a high-frequency electric field for applying a high-frequency electric field
  • a second high-frequency electric field applying device that applies a high-frequency electric field having a frequency different from that of the first high-frequency electric field applying device.
  • FIG. 1 is a configuration diagram of a particle beam therapy system according to Embodiment 1 of the present invention.
  • FIG. 2 is a perspective view of a main magnetic field magnet arranged in the accelerator of the particle beam therapy system according to the first embodiment.
  • FIG. 3 is a cross-sectional view of the main magnetic field magnet according to the first embodiment taken along a vertical plane.
  • FIG. 3 is a plan view of the main magnetic field magnet according to the first embodiment as viewed from an intermediate plane. It is sectional drawing by the intermediate plane of the high frequency kicker in Example 1.
  • FIG. 3 is a cross-sectional view of the high-frequency kicker according to the first embodiment, taken along a vertical plane.
  • FIG. 3 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the first embodiment.
  • FIG. 3 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the first embodiment.
  • FIG. 3 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the first embodiment.
  • FIG. 9 is a plan view of a main magnetic field magnet according to a second embodiment of the present invention as viewed from an intermediate plane.
  • FIG. 10 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the second embodiment.
  • FIG. 10 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the second embodiment.
  • FIG. 10 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the second embodiment.
  • FIG. 10 is an enlarged plan view of one of the protrusions of the main magnetic field magnet in the second embodiment. It is sectional drawing by the intermediate plane of the high frequency kicker in Example 2.
  • the first problem is to share the output channel of the beam from low energy to high energy.
  • the second problem is to reduce the magnetic field required for the septum.
  • the third problem is to apply a gradient magnetic field selectively to the extracted beam.
  • a magnetic field is often used to generate a static gradient magnetic field near the beam path of the maximum energy in order to extract only the beam with the maximum energy.
  • a structure in which a gradient magnetic field is selectively applied to a beam of any energy from low energy to high energy for example, in the case of a proton beam therapy system, from 70 MeV to 230 MeV, as needed to extract. I need a way.
  • variable energy small particle beam accelerator which solves these three problems without using the above-described degrader, and a particle beam therapy apparatus including the accelerator will be described with reference to the drawings.
  • FIG. 1 is a configuration diagram of the particle beam therapy system according to the first embodiment.
  • FIG. 2 is a perspective view of the main magnetic field magnet arranged in the accelerator.
  • FIG. 3 is a sectional view of the main magnetic field magnet taken along a vertical plane.
  • 4 is a plan view of the main magnetic field magnet viewed from an intermediate plane,
  • FIG. 5 is a cross-sectional view of the high-frequency kicker taken along an intermediate plane,
  • FIG. 6 is a cross-sectional view of the high-frequency kicker taken along a vertical plane, and
  • FIGS. It is the top view which expanded one of the parts.
  • the particle beam therapy system 1001 is installed on the floor of a building (not shown).
  • the particle beam therapy system 1001 includes an ion beam generator 1002, a beam transport system 1013, a rotating gantry 1006, an irradiation device 1007, and a control system 1065.
  • the ion beam generator 1002 includes an ion source 1003 and an accelerator 1004 to which the ion source 1003 is connected. Details of the accelerator 1004 will be described later.
  • the beam transport system 1013 has a beam path 1048 reaching the irradiation device 1007, and a plurality of quadrupole electromagnets 1046, a deflection electromagnet 1041, and a plurality of quadrupole electromagnets are provided on the beam path 1048 from the accelerator 1004 toward the irradiation device 1007. 1047, a bending electromagnet 1042, quadrupole electromagnets 1049 and 1050, and bending electromagnets 1043 and 1044 are arranged in this order.
  • a part of the beam path 1048 of the beam transport system 1013 is installed in the rotating gantry 1006, and the bending electromagnet 1042, the quadrupole electromagnets 1049 and 1050, and the bending electromagnets 1043 and 1044 are also installed in the rotating gantry 1006.
  • the beam path 1048 is connected to an emission channel 1019 provided in the accelerator 1004.
  • the rotating gantry 1006 is configured to be rotatable about a rotating shaft 1045, and is a rotating device that rotates the irradiation device 1007 around the rotating shaft 1045.
  • the irradiation device 1007 includes two scanning electromagnets 1051 and 1052, a beam position monitor 1053, and a dose monitor 1054.
  • the scanning electromagnets 1051 and 1052, the beam position monitor 1053, and the dose monitor 1054 are arranged along the central axis of the irradiation device 1007, that is, along the beam axis.
  • the scanning electromagnets 1051 and 1052, the beam position monitor 1053, and the dose monitor 1054 are arranged in a casing (not shown) of the irradiation device 1007.
  • the beam position monitor 1053 and the dose monitor 1054 are arranged downstream of the scanning electromagnets 1051 and 1052.
  • the scanning electromagnet 1051 and the scanning electromagnet 1052 deflect the ion beam, respectively, and scan the ion beam in directions perpendicular to each other on a plane perpendicular to the central axis of the irradiation device 1007.
  • the beam position monitor 1053 measures the passing position of the irradiated beam.
  • the dose monitor 1054 measures the dose of the irradiated beam.
  • the irradiation device 1007 is attached to the rotating gantry 1006, and is arranged downstream of the bending electromagnet 1044.
  • a treatment table 1055 on which the patient 1056 lies is arranged so as to face the irradiation device 1007.
  • the control system 1065 includes a central control unit 1066, an accelerator / transport system control unit 1069, a scan control unit 1070, a rotation control unit 1088, and a database 1072.
  • the central controller 1066 has a central processing unit (CPU) 1067 and a memory 1068 connected to the CPU 1067.
  • the accelerator / transport system controller 1069, the scanning controller 1070, the rotation controller 1088, and the database 1072 are connected to the CPU 1067 in the central controller 1066.
  • the particle beam therapy system 1001 further has a treatment planning device 1073, and the treatment planning device 1073 is connected to the database 1072.
  • the irradiation energy and the irradiation angle of the particle beam are created as a treatment plan by the treatment planning device 1073 prior to the irradiation of the particle beam, and the irradiation is executed based on the treatment plan.
  • the CPU 1067 of the central controller 1066 reads various operation control programs related to irradiation of each device constituting the particle beam therapy system 1001 from the treatment plan stored in the database 1072, executes the read program, and executes the accelerator. Outputting a command via the transport system control device 1069, the scan control device 1070, and the rotation control device 1088, controls the operation of each device in the particle beam therapy system 1001.
  • the control processing of the operation to be executed may be integrated into one program, may be divided into a plurality of programs, or may be a combination thereof.
  • Part or all of the program may be realized by dedicated hardware or may be modularized. Furthermore, various programs may be installed in each device by a program distribution server or an external storage medium.
  • the control devices may be independent devices connected by a wired or wireless network, or two or more control devices may be integrated.
  • the beam current measuring device 1098 includes a moving device 1017 and a position detector 1039.
  • the high-frequency power supply 1036 inputs electric power to the high-frequency acceleration cavity 1037 provided in the accelerator 1004 through the waveguide 1010 and generates a high-frequency electric field for accelerating a beam between the electrode connected to the high-frequency acceleration cavity 1037 and the ground electrode.
  • the accelerator 1004 of this embodiment it is necessary to modulate the resonance frequency of the high-frequency acceleration cavity 1037 in accordance with the energy of the beam.
  • the inductance or the capacitance may be adjusted.
  • a known method can be used for adjusting the inductance and the capacitance.
  • a high-frequency acceleration cavity 1037 is connected to a variable capacitor for control.
  • the main magnetic field magnet 1 is a magnet that generates a static magnetic field, and has, as main components, an upper return yoke 4 and a lower return yoke 5 that have a substantially disk shape when viewed from the vertical direction as shown in FIG. are doing.
  • the upper return yoke 4 and the lower return yoke 5 have a shape that is substantially vertically symmetric with respect to the intermediate plane 2.
  • the intermediate plane 2 substantially passes through the center of the main magnetic field magnet 1 in the vertical direction, and substantially coincides with the orbital plane drawn by the beam being accelerated.
  • the upper return yoke 4 and the lower return yoke 5 have a shape that is perpendicular to the intermediate plane 2 and is generally plane-symmetric with respect to the vertical plane 3 that is a plane passing through the center of the main magnetic field magnet 1 with respect to the intermediate plane 2.
  • an intersecting portion of the intermediate plane 2 with the main magnetic field magnet 1 is indicated by an alternate long and short dash line, and an intersecting portion of the vertical plane 3 with the main magnetic field magnet 1 is indicated by a broken line.
  • An ion source 1003 is arranged in the upper return yoke 4.
  • a coil 6 is arranged in a space surrounded by the upper return yoke 4 and the lower return yoke 5 symmetrically with respect to the intermediate plane 2.
  • the ion source 1003 is installed outside the main magnetic field magnet 1 assuming an external ion source, and the through-hole 24 is provided in correspondence with the ion source 1003. May be installed inside.
  • the coil 6 is a superconducting coil, which is installed inside a cryostat (not shown) and is cooled by a refrigerant such as liquid helium or heat transfer from a refrigerator (not shown).
  • the coil 6 is connected to the coil excitation power supply 1057 by the coil extraction wiring 1022 shown in FIG.
  • a vacuum vessel 7 is provided inside the coil 6 in a space surrounded by the upper return yoke 4 and the lower return yoke 5.
  • an upper magnetic pole 8 is disposed on a surface of the upper return yoke 4 facing the lower return yoke 5. Further, a lower magnetic pole 9 is disposed on a surface of the lower return yoke 5 facing the upper return yoke 4. The upper magnetic pole 8 and the lower magnetic pole 9 are arranged in plane symmetry with respect to the intermediate plane 2.
  • the upper return yoke 4, the lower return yoke 5, the upper magnetic pole 8, and the lower magnetic pole 9 are made of, for example, pure iron with low impurity concentration, low carbon steel, or the like.
  • the vacuum container 7 is made of stainless steel or the like.
  • the coil 6 is made of a superconducting wire using a superconductor such as niobium titanium.
  • a space for rotating and accelerating the ion beam is formed between the upper magnetic pole 8 and the lower magnetic pole 9.
  • the emission channel 1019 includes an electromagnet called a septum, and is connected to the emission channel power supply 1082 shown in FIG. By supplying a current from the power supply for emission channel 1082 to the electromagnet provided in the emission channel 1019, the ion beam that has reached the emission channel 1019 is adjusted and sent to the beam transport system 1013.
  • FIG. 4 is a plan view of the facing surface 10 as viewed from the intermediate plane 2. Since the main magnetic field magnet 1 has a plane-symmetric structure with respect to the intermediate plane 2, a detailed structure of the main magnetic field magnet 1 will be described below with reference to FIGS.
  • Concave portions 21a, 21b, 21c, 21d and convex portions 22a, 22b, 22c, 22d are formed on a surface of the upper magnetic pole 8 and the lower magnetic pole 9 facing the intermediate plane 2, respectively. As shown, the concave portions 21a, 21b, 21c, 21d and the convex portions 22a, 22b, 22c, 22d are alternately arranged along the circling direction of the beam orbit 23.
  • the concave portions 21a, 21b, 21c, 21d and the convex portions 22a, 22b, 22c, 22d may be formed integrally with the upper magnetic pole 8 and the lower magnetic pole 9, or may be formed as a separate member and then formed as an upper magnetic pole. At the time of assembly, it may be engaged with the surface of the lower magnetic pole 8 or the lower magnetic pole 9 by a known method such as welding or bolting.
  • the material is desirably the same as the upper magnetic pole 8 and the lower magnetic pole 9.
  • a gradient magnetic field magnet 31 (peeler), a gradient magnetic field magnet 32 (regenerator), and a high-frequency kicker 40 are provided in the concave portion 21a in which the emission channel 1019 is disposed in the vicinity. .
  • the gradient magnets 31 and 32 are coils that generate a gradient magnetic field for displacing the beam trajectory.
  • the gradient magnetic field magnet 31 is preferably a coil that generates a gradient magnetic field in which the magnetic field distribution of the generated gradient magnetic field decreases in the magnetic field strength radially outward of the accelerator 1004.
  • the gradient magnetic field magnet 32 is a coil that generates a gradient magnetic field in which the magnetic field distribution of the generated gradient magnetic field increases in radial direction and the magnetic field strength increases outward.
  • the gradient magnetic field magnets 31 and 32 can be replaced with a structure integrally formed with the concave portion 21a instead of the coil.
  • a structure integrally formed with the concave portion 21a examples include a structure manufactured as a separate member and then engaged with the concave portion 21a by a known method such as welding or bolting. More specifically, a magnetic substance can be further added to the surface of the concave portion 21a, or the surface shape of the concave portion 21a can be processed.
  • the gradient magnetic field magnet 31 is disposed near the convex portion 22d of the concave portion 21a and the gradient magnetic field magnet 32 is disposed near the convex portion 22a of the concave portion 21a, This position can be reversed.
  • the magnetic field in the region from the outer peripheral surface of the magnetic pole to the inner peripheral surface of the yoke decreases radially outward, the gradient that generates a gradient magnetic field in which the magnetic field intensity decreases radially outward.
  • the magnetic field magnet 31 may be omitted in some cases.
  • the gradient magnetic field generated by the gradient magnetic field magnets 31 and 32 desirably includes at least a quadrupole magnetic field component, and desirably includes a multipolar magnetic field having four or more poles or a dipole magnetic field.
  • the through hole 18 is a through hole for installing the beam transport system 1013.
  • the through hole 19 is provided so as to be symmetric with the through hole 18 with respect to the vertical plane 3 in order to increase the symmetry of the main magnetic field magnet and to increase the accuracy of the magnetic field generated by the main magnetic field magnet. .
  • FIG. 5 is a sectional view of the high-frequency kicker 40 taken along the intermediate plane 2.
  • FIG. 6 is a sectional view of the high-frequency kicker 40 taken along the vertical plane 3.
  • the high-frequency kicker 40 shown in FIGS. 2, 5, and 6 is a device for applying a high-frequency electric field having a frequency different from that of the high-frequency accelerating cavity 1037, and is similar to the gradient magnetic field magnet 31 and the gradient magnetic field magnet 32 as shown in FIG. Are arranged in a space interposed between the concave portions 21a.
  • An emission channel 1019 for extracting a beam accelerated to a predetermined energy out of the accelerator 1004 is provided in a magnetic pole outer peripheral region of the concave portion 21 a provided with the gradient magnetic field magnet 31, the gradient magnetic field magnet 32, and the high frequency kicker 40. .
  • the high-frequency kicker 40 includes a ground electrode 41 and a high-voltage electrode 42.
  • the ground electrode 41 is provided on the inner peripheral side
  • the high-voltage electrode 42 is provided on the outer peripheral side.
  • the ground electrode 41 and the high-voltage electrode 42 have shapes substantially parallel to the curve of the beam trajectory so that the high-frequency electric field acts in a direction orthogonal to the beam trajectory in the intermediate plane. Designed for
  • a metal projection 43 is attached to the ground electrode 41, so that the concentration of the high-frequency electric field generated between the ground electrode 41 and the high-voltage electrode 42 can be increased.
  • the high-voltage electrode 42 Since a high-frequency voltage is applied to the high-voltage electrode 42, the high-voltage electrode 42 is supported by the ground electrode 41 via the insulating support 45 as shown in FIG.
  • the ground electrode 41 is supported by the upper magnetic pole 8 and the lower magnetic pole 9 via a non-magnetic support 44.
  • the ground electrode 41 and the high-voltage electrode 42 are both vertically divided about the intermediate plane 2 through which the beam passes.
  • the high-frequency kicker 40 of the present embodiment has a shape with an open end face as shown in FIG. 6, the end face may be closed with a ground electrode except for a beam passage hole to form a resonator structure.
  • the main magnetic field magnet 1 In order to determine the size of the main magnetic field magnet 1, it is necessary to determine the magnetic field strength and the radius of the beam orbit at the highest energy. As the magnetic field generated by the main magnetic field magnet 1 is larger, the spread of the beam trajectory becomes smaller, and the accelerator 1004 and, consequently, the particle beam therapy system 1001 can be downsized.
  • the magnetic field at the incident point was set to 5 [T]
  • the beam radius of the highest energy was set to 1 [m].
  • the position of the incident point of the beam to be accelerated and the position of the center O1 of the maximum beam energy trajectory are matched.
  • the magnetic field is designed based on the principle of weak convergence in order to stably circulate the beam.
  • an amount called an n index as shown in the following equation (1) is used.
  • B is the magnetic field in the intermediate plane 2
  • ⁇ is the radius of curvature of the beam orbit
  • the magnetic field gradient ⁇ B / ⁇ r is perpendicular to the beam traveling direction on the intermediate plane 2 with respect to the direction in which the beam energy increases. The derivative of the magnetic field is shown.
  • ⁇ B / ⁇ r is ⁇ 1 [T / m].
  • the value should be smaller than 0.
  • ⁇ B / ⁇ r is -0.5 [T / m].
  • the beam radius of the highest energy is 1 [m]
  • the magnetic field on this orbit is 4.5 [T].
  • the magnetic pole shape is often axially symmetric in order to generate an axially symmetric magnetic field distribution. Then, the magnetic field B becomes a constant value along the beam circling direction.
  • the principle of weak convergence does not necessarily require that B is constant in the beam circling direction, and is valid even when B is an average magnetic field in the beam circling direction. That is, the strength of the magnetic field may be distributed in the beam circling direction.
  • the four concave portions 21a, 21b, 21c, and 21d and the four convex portions 22a, 22b, 22c, and 22d distribute the magnetic field in the beam circling direction, and the magnetic field in the beam circulating direction.
  • the average was designed to decrease according to equation (1) with increasing beam energy.
  • the distance between the upper magnetic pole 8 and the lower magnetic pole 9 becomes shorter, so that the region is sandwiched between the upper and lower concave portions 21a, 21b, 21c, and 21d.
  • the magnetic field is larger than in the region that has been set.
  • the narrowing of the angular widths ⁇ 1 , ⁇ 2 , ⁇ 3 ,..., ⁇ n of the protruding portions 22 a, 22 b, 22 c, and 22 d depends on the present embodiment when viewed from the center O 1 of the beam orbit. Means that the angular width of the concave portions 21a, 21b, 21c, 21d becomes wider as the beam energy increases.
  • the magnetic field in the region between the concave portions 21a, 21b, 21c, and 21d and the magnetic field in the region between the convex portions 22a, 22b, 22c, and 22d are considered to be constant values, and are determined by Expression (1). Adjustment may be made so that the angular width of the projections 22a, 22b, 22c, 22d decreases in accordance with the decrease in the average magnetic field.
  • L n is a turn in a decrease followed by an increase with increasing beam energy (L x> L 2> L 1) (L x> L n) relationship.
  • the protrusions 22a, 22b, 22c, and 22d have a tangent at a boundary between the protrusion 22c and the recess 21d and a tangent at a boundary between the protrusion 22c and the recess 21c on the opposite side.
  • ⁇ ′ 1 > ⁇ ′ 2 are reduced as the beam energy increases.
  • the magnetic field obtained in this way can have an average magnetic field for the highest energy beam of 4.5 [T], which is the same value as when the magnetic poles are axisymmetric, so that the size of the accelerator is the same.
  • the magnetic field with respect to the beam having the highest energy is uniformly 4.5 [T]. T].
  • the magnetic field to be generated by the emission channel 1019 for beam extraction is provided.
  • the beam accelerated to the maximum energy senses the gradient magnetic field generated by the gradient magnetic field magnet 31 and the gradient magnetic field magnet 32, so that a resonance phenomenon occurs in the horizontal movement of the beam, and the beam moves from the equilibrium orbit. Is increased, and the beam reaching the exit channel 1019 is extracted outside the accelerator.
  • the gradient magnetic field generated by the gradient magnetic field magnet 31 and the gradient magnetic field magnet 32 is corrected radially inward of the gradient magnetic field magnet 31 and the gradient magnetic field magnet 32 so that the influence of the gradient magnetic field is sufficiently small inside the beam orbit of the maximum energy. It is desirable to install a magnetic material and a coil (not shown).
  • the low-energy beam approaching the extraction energy must be destabilized in the horizontal direction. It is necessary to balance the two of acceleration.
  • a mechanism for selectively applying a gradient magnetic field such as applying a gradient magnetic field generated by the gradient magnetic field magnets 31 and 32 only at that timing, is required.
  • the mechanism for this is the high-frequency kicker 40.
  • the role of the high-frequency kicker 40 is to make the beam to be extracted selectively feel the magnetic field of the gradient magnetic field magnets 31 and 32.
  • the beam that is incident and accelerated from the ion source gradually increases its average orbital radius, and finally passes through the inside of the high-frequency kicker 40.
  • the high-frequency power source 1036 is turned off to cut off the high-frequency electric field excited between the electrode connected to the high-frequency accelerating cavity 1037 and the ground electrode. Turn on.
  • the frequency of the high-frequency kicker 40 is set to be substantially the same as f rev ⁇ ⁇ . Then, a high-frequency electric field of the high-frequency kicker 40 is applied.
  • the beam trajectory receives a radially outward force, and the beam trajectory is gradually shifted radially outward, and finally, the gradient magnetic field magnets 31 and 32 are generated. It reaches a position where the user can feel the gradient magnetic field.
  • the beam that has begun to feel the gradient magnetic field of the gradient magnetic field magnets 31 and 32 begins to diverge in the amplitude of the horizontal betatron motion, and finally reaches the exit channel 1019 and is taken out of the accelerator.
  • the accelerator 1004 includes a main magnetic field magnet 1 that generates a static magnetic field, and a high-frequency acceleration that can modulate a frequency and applies a high-frequency electric field for accelerating a beam.
  • the main magnetic field magnet 1 includes a cavity 1037 and a high-frequency kicker 40 for applying a high-frequency electric field having a frequency different from that of the high-frequency acceleration cavity 1037.
  • the main magnetic field magnet 1 is fixed to the upper return yoke 4 and the lower return yoke 5.
  • the upper magnetic pole 8 and the lower magnetic pole 9 are arranged at a plane symmetric position with respect to the intermediate plane 2 in a space sandwiched between the upper magnetic pole 8 and the lower magnetic pole 9.
  • the concave portions 21a, 21b, 21c, 21d and the convex portions 22a, 22b, 22c, 22d cross along the beam circling direction.
  • the high-frequency kicker 40 is arranged in space between the concave portion 21a.
  • the high-performance and large-sized emission channel 1019 provided only in one is provided.
  • a beam having a predetermined energy can be extracted without arranging a septum electromagnet in which measures such as conversion are taken. Therefore, it is possible to provide a small particle beam accelerator 1004 in which the energy of the extracted beam is continuously variable without using a plurality of emission channels and without using a degrader.
  • the accelerator 1004 having such a configuration is suitable for a particle beam therapy system which is expected to realize a high irradiation dose rate and improve the treatment throughput of a patient.
  • the gradient magnetic field magnets 31 and 32 for generating a gradient magnetic field for displacing the beam trajectory are arranged in a space between the concave portions 21 a provided with the high frequency kicker 40, the high frequency kicker 40 is displaced.
  • the arrangement can be such that the low-energy beam surely senses the gradient magnetic field. This allows the beam of predetermined energy to reach the emission channel 1019 more efficiently by expanding the horizontal betatron oscillation amplitude in the horizontal direction, and it is possible to extract the beam outside the accelerator.
  • an emission channel 1019 for extracting a beam accelerated to a predetermined energy to the outside of the accelerator 1004 is provided in a magnetic pole outer peripheral region of the concave portion 21 a provided with the high frequency kicker 40, so that the beam is displaced by the high frequency kicker 40.
  • the beam with the increased horizontal betatron oscillation amplitude can more easily reach the exit channel 1019.
  • the convex portions 22a, 22b, 22c, and 22d have a main magnetic field due to the fact that the angular width ⁇ of the convex portions 22a, 22b, 22c, and 22d as viewed from the center of the beam orbit decreases as the beam energy increases. Is increased, the beam can be accelerated stably without increasing the size of the accelerator. Further, the magnetic field strength in the outer peripheral region of the magnetic pole where the entrance of the exit channel 1019 serving as the exit of the accelerated beam can be reduced. For this reason, it is possible to provide a small accelerator having a main magnetic field magnet from which a beam can be easily extracted without using a difficult method such as high performance and large size of the septum.
  • the high-frequency electric field by the high-frequency accelerating cavity 1037 is shut off, and the application of the high-frequency electric field by the high-frequency kicker 40 is started, so that the energy of the beam to be extracted can be selected with high accuracy. it can.
  • the component of the multipole magnetic field generated by the gradient magnetic field magnet 32 has a magnetic field gradient in which the magnetic field strength increases toward the radially outer side
  • the component of the multipole magnetic field generated by the gradient magnetic field magnet 31 Has a magnetic field gradient that reduces the magnetic field strength toward the radially outer side, which can destabilize the betatron oscillation in the orbital plane for the beam with the specific energy to be extracted. Therefore, it is possible to obtain an effect that a beam having an arbitrary energy can be more easily extracted.
  • Example 2 Second Embodiment A particle accelerator and a particle beam therapy system according to a second embodiment of the present invention will be described with reference to FIGS.
  • the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
  • FIG. 10 is a plan view of the main magnetic field magnet according to the second embodiment viewed from an intermediate plane.
  • 11 to 14 are enlarged plan views of one of the projections of the main magnetic field magnet.
  • FIG. 15 is a cross-sectional view of the high-frequency kicker taken along an intermediate plane.
  • the particle beam accelerator of the second embodiment is different from the particle beam accelerator of the first embodiment in the shape of the surfaces of the upper magnetic pole and the lower magnetic pole in the main magnetic field magnet.
  • ⁇ can be redefined from a function of the radial distance r to a function of the kinetic energy K.
  • FIG. 10 is a plan view of the opposing surface 10 according to the second embodiment as viewed from the intermediate plane 2. About the same structure etc. as Example 1, the same number is diverted and pointed out.
  • the beam incident point is O2
  • the orbital center of the highest energy beam orbit 126 is O4
  • the orbital center of the intermediate energy beam orbit 127 is O3
  • the center of the energy beam orbit accelerated from the middle is O3.
  • the width 128 from the incident point to the beam orbit of the maximum energy is set to 0.1 [m]. Then, assuming that ⁇ B / -r is -1.0 [T / m] as in the first embodiment, the magnetic field for the highest energy is 4.9 [T].
  • ⁇ nA narrows according to the increase of the beam energy according to Expressions (2) and (3) ( ⁇ 1A > ⁇ 2A > ⁇ 3A >>...> ⁇ nA ).
  • the angle widths ⁇ 1B , ⁇ 2B ,..., ⁇ nB of the convex portion 122d when viewed from the centers O3, O5, and O4 of the beam orbit are expressed by the equations (2) and ( According to 3), the beam energy becomes narrower as the beam energy increases ( ⁇ 1B > ⁇ 2B >>...> ⁇ nB ).
  • the distance L 1A , L 2A ,..., L nA at which the accelerated beam passes through one convex portion 122c increases as the beam energy increases, as shown in FIG. increase (L 2A> L 1A) to turn to decrease after the (L 2A> L xA> L nA) relationship.
  • the angle between the tangent to the boundary between the convex portion 122c and the concave portion 121d and the tangent to the boundary line between the convex portion 122c and the concave portion 121c on the opposite side is a beam. It decreases with increasing energy, after which the two tangents become parallel. Thereafter, the angle becomes larger ( ⁇ ′ 3A >>... ⁇ ′ nA ).
  • the convex portion 122c and the convex portion 122b symmetrical with respect to the vertical plane 3 are the same as the convex portion 122c.
  • the convex portion 122a having a shape symmetrical to the convex portion 122d and the vertical plane 3 is the same as the convex portion 122d.
  • the average magnetic field along the beam circling direction can be set to the same value as 4.9 [T] when the magnetic poles are axisymmetric, so that the size of the accelerator is axisymmetric. Is equivalent to
  • the magnetic field for the beam with the highest energy is constant at 4.9 [T] along the beam circling direction, but in the second embodiment, 4.9 in the concave portions 121a, 121b, 121c, and 121d.
  • the magnetic field is less than [T], and the magnetic field exceeds 4.9 [T] in the convex portions 122a, 122b, 122c, and 122d.
  • the entrance of the emission channel 1019 for taking out the beam accelerated to the predetermined energy to the outside of the accelerator 1004 is set near the magnetic pole outer peripheral surface 125 of the concave portion 121a.
  • the magnetic field to be generated by the emission channel 1019 for beam extraction can be made smaller than the axially symmetric magnetic pole shape, and the beam extraction can be facilitated.
  • the orbital center O4 of the highest energy does not coincide with the incident point O2, and the incident point O2 is shifted toward the beam entrance of the exit channel 1019.
  • the center of the beam trajectory is shifted in this way, the low-energy beam trajectory approaches the entrance of the emission channel 1019 on the concave portion 121a side, so that a region where the beam trajectory is dense is formed on the emission channel 1019 side.
  • the energy band of the beam orbit passing through the high-frequency kicker 40 increases. That is, as compared with the first embodiment, the second embodiment passes through the high-frequency kicker 40 to a lower energy beam orbit.
  • the lower-energy beam orbit than in the first embodiment can be applied to the gradient magnetic field generated by the gradient magnetic field magnets 31 and 32. Can be passed nearby.
  • the gradient magnetic field magnet 31 and the gradient magnetic field magnet 32 is preferably arranged in a direction in which the beam trajectory is shifted by the high-frequency kicker 40 and is closer to the vertical plane 3.
  • the gradient magnetic field magnet 31 and the gradient magnetic field magnet 32 have the smallest volume of the concave portion 121a in the space between the concave portions 121a, 121b, 121c, and 121d. It is preferable to arrange them in a space between them.
  • the low energy beam displaced by the high frequency kicker 40 can surely feel the gradient magnetic field, and the amplitude of the betatron oscillation in the horizontal direction increases. Reaches the emission channel 1019 and can be taken out of the accelerator.
  • the particle beam accelerator and the particle beam therapy system according to the second embodiment of the present invention can provide substantially the same effects as those of the particle beam accelerator and the particle beam therapy system according to the first embodiment.
  • the space between the concave portions 121a in which the high-frequency kicker 40 and the gradient magnetic field magnets 31 and 32 are arranged has the smallest volume among the spaces between the concave portions 121a, 121b, 121c and 121d.
  • a region where the beam orbit becomes dense can be provided on the outer periphery of the magnetic pole where the entrance of the emission channel 1019 is installed.
  • the magnetic field to be generated by the emission channel 1019 for beam extraction can be reduced as compared with the case where the magnetic pole shape is symmetrical with respect to the axis. Therefore, from these effects, it is possible to more easily extract the beam accelerated to the predetermined energy.
  • a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, for a part of the configuration of each embodiment, it is also possible to add / delete / replace another configuration.
  • the particles to be accelerated are not specified. That is, regardless of whether protons are supplied from the ion source 1003 or carbon ions are supplied from the ion source 1003, the frequency of the high-frequency accelerating cavity 1037 is adjusted in accordance with each of the accelerating particles to stably rotate the beam. Can be done.
  • the particles to be accelerated are not limited to the protons and carbon ions described above, but may be heavy particle ions other than carbon ions such as helium ions.
  • the number of the concave portions and the number of the convex portions provided in the upper magnetic pole 8 and the lower magnetic pole 9 are each four, but the number of the concave portions and the convex portions is not limited to four. If it is an integer of 3 or more, it is possible to generate a magnetic field such that the beam circulates stably.
  • the ion beam generator directly connects the ion beam generator and the rotating gantry or the irradiation device without providing the beam transport system. Can be.
  • the rotating gantry 1006 is used as an apparatus for irradiating a particle beam used for treatment
  • a fixed irradiation apparatus can be used.
  • the number of irradiation devices is not limited to one, and a plurality of irradiation devices can be provided.
  • the scanning method using the scanning electromagnets 1051 and 1052 has been described as an irradiation method.
  • An irradiation method that forms a dose distribution can also be applied to the present invention.
  • the accelerator is used for particle beam therapy.
  • the application of the accelerator is not limited to particle beam therapy, and the accelerator can be used for high energy experiments, PET (Positron Emission Tomography) drug generation, and the like.
  • High frequency kicker (second high frequency electric field applying device) 41 Ground electrode 42 High voltage electrode 43 Projection 44 Nonmagnetic support 45 Insulating support 128 Beam trajectory width 1001 Particle beam therapy system 1004 Accelerator (particle beam accelerator) 1019: emission channel 1037: high-frequency accelerating cavity (first high-frequency electric field applying device)

Landscapes

  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Biomedical Technology (AREA)
  • Radiology & Medical Imaging (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Pathology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Particle Accelerators (AREA)
  • Radiation-Therapy Devices (AREA)

Abstract

La présente invention comprend : un aimant de champ magnétique principal 1 pour générer un champ magnétique statique ; une cavité d'accélération haute fréquence à fréquence variable 1037 pour appliquer un champ électrique haute fréquence pour une accélération de faisceau ; et un déflecteur haute fréquence 40 pour appliquer un champ électrique haute fréquence ayant une fréquence différente de celle de la cavité d'accélération haute fréquence 1037. Des parties concaves 21a, 21b, 21c, 21d et des parties convexes 22a, 22b, 22c, 22d sont disposées en alternance le long d'une direction d'orbite de faisceau sur des surfaces d'un pôle magnétique supérieur 8 et d'un pôle magnétique inférieur 9 de l'aimant de champ magnétique principal 1 faisant face à un plan intermédiaire 2, et le déflecteur haute fréquence 40 est disposé dans un espace entre les parties concaves 21a.
PCT/JP2019/005847 2018-08-31 2019-02-18 Accélérateur de faisceau de particules, et système de thérapie par faisceau de particules WO2020044604A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2018163888A JP2020035728A (ja) 2018-08-31 2018-08-31 粒子線加速器および粒子線治療システム
JP2018-163888 2018-08-31

Publications (1)

Publication Number Publication Date
WO2020044604A1 true WO2020044604A1 (fr) 2020-03-05

Family

ID=69645137

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2019/005847 WO2020044604A1 (fr) 2018-08-31 2019-02-18 Accélérateur de faisceau de particules, et système de thérapie par faisceau de particules

Country Status (2)

Country Link
JP (1) JP2020035728A (fr)
WO (1) WO2020044604A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3876679A1 (fr) * 2020-03-06 2021-09-08 Ion Beam Applications Synchrocyclotron permettant d'extraire des poutres de différentes énergies

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2022190590A (ja) * 2021-06-14 2022-12-26 株式会社日立製作所 粒子線加速器、および、粒子線治療システム

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11329796A (ja) * 1998-05-11 1999-11-30 Mitsubishi Electric Corp 等時性サイクロトロン
WO2016174700A1 (fr) * 2015-04-27 2016-11-03 株式会社日立製作所 Accélérateur circulaire
JP2017204337A (ja) * 2016-05-09 2017-11-16 日本メジフィジックス株式会社 サイクロトロン制御装置、サイクロトロン、サイクロトロン制御プログラムおよび放射性薬剤の製造方法
JP2018060803A (ja) * 2017-11-22 2018-04-12 住友重機械工業株式会社 サイクロトロン

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11329796A (ja) * 1998-05-11 1999-11-30 Mitsubishi Electric Corp 等時性サイクロトロン
WO2016174700A1 (fr) * 2015-04-27 2016-11-03 株式会社日立製作所 Accélérateur circulaire
JP2017204337A (ja) * 2016-05-09 2017-11-16 日本メジフィジックス株式会社 サイクロトロン制御装置、サイクロトロン、サイクロトロン制御プログラムおよび放射性薬剤の製造方法
JP2018060803A (ja) * 2017-11-22 2018-04-12 住友重機械工業株式会社 サイクロトロン

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3876679A1 (fr) * 2020-03-06 2021-09-08 Ion Beam Applications Synchrocyclotron permettant d'extraire des poutres de différentes énergies
JP2021141062A (ja) * 2020-03-06 2021-09-16 イオン ビーム アプリケーションズ ソシエテ アノニムIon Beam Applications S.A. 各種のエネルギーのビームを取り出すためのシンクロサイクロトロン
US11160159B2 (en) 2020-03-06 2021-10-26 Ion Beam Applications S.A. Synchrocyclotron for extracting beams of various energies
JP7288473B2 (ja) 2020-03-06 2023-06-07 イオン ビーム アプリケーションズ ソシエテ アノニム 各種のエネルギーのビームを取り出すためのシンクロサイクロトロン

Also Published As

Publication number Publication date
JP2020035728A (ja) 2020-03-05

Similar Documents

Publication Publication Date Title
WO2020044604A1 (fr) Accélérateur de faisceau de particules, et système de thérapie par faisceau de particules
JP7240262B2 (ja) 加速器、粒子線治療システムおよびイオン取り出し方法
WO2019097721A1 (fr) Système de thérapie par faisceau de particules, accélérateur et procédé de fonctionnement d'un accélérateur
WO2019220714A1 (fr) Accélérateur de faisceau de particules, et système de traitement par faisceau de particules
WO2019097904A1 (fr) Accélérateur et système de thérapie par faisceau de particules
JP2019096404A (ja) 円形加速器および粒子線治療システム
JP2020170688A (ja) 粒子線加速器および粒子線治療システム
WO2019093110A1 (fr) Accélérateur circulaire et système de traitement de faisceau de particules
US20230389169A1 (en) Accelerator and particle therapy system
WO2022168484A1 (fr) Accélérateur et système de thérapie par faisceau de particules
JP2020064753A (ja) 加速器、およびそれを用いた加速器システム、粒子線治療システム
WO2018096648A1 (fr) Accélérateur et dispositif de projection de faisceau de particules
JP7319144B2 (ja) 円形加速器および粒子線治療システム、円形加速器の作動方法
WO2022264475A1 (fr) Accélérateur de faisceau de particules, et système de thérapie par faisceau de particules
JP2022026175A (ja) 加速器および粒子線治療装置
EP4240117A1 (fr) Accélérateur et système de thérapie par particules
JP2024068279A (ja) 加速器及び粒子線治療システム、並びに加速器の調整方法
WO2024079992A1 (fr) Accélérateur et dispositif thérapeutique à faisceau de particules
US20240023225A1 (en) Accelerator and particle therapy system
JP6663618B2 (ja) 加速器および粒子線照射装置
JP7303138B2 (ja) 円形加速器、粒子線治療システム、同位元素製造システム、および、放射性薬剤製造システム
WO2019097618A1 (fr) Accélérateur de rayons de particules et dispositif thérapeutique à rayons de particules l'utilisant
JP2024055638A (ja) 円形加速器及び粒子線治療装置、並びに円形加速器の運転方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19854898

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19854898

Country of ref document: EP

Kind code of ref document: A1