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WO2018092483A1 - Accélérateur, dispositif d'exposition à un faisceau de particules et procédé d'extraction de faisceau - Google Patents

Accélérateur, dispositif d'exposition à un faisceau de particules et procédé d'extraction de faisceau Download PDF

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Publication number
WO2018092483A1
WO2018092483A1 PCT/JP2017/037387 JP2017037387W WO2018092483A1 WO 2018092483 A1 WO2018092483 A1 WO 2018092483A1 JP 2017037387 W JP2017037387 W JP 2017037387W WO 2018092483 A1 WO2018092483 A1 WO 2018092483A1
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WIPO (PCT)
Prior art keywords
accelerator
coil
magnetic field
electrode
built
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Ceased
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PCT/JP2017/037387
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English (en)
Japanese (ja)
Inventor
隆光 羽江
孝道 青木
孝義 関
重充 原
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Hitachi Ltd
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Hitachi Ltd
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Filing date
Publication date
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Publication of WO2018092483A1 publication Critical patent/WO2018092483A1/fr
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    • 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
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K5/00—Irradiation devices
    • G21K5/04—Irradiation devices with beam-forming means
    • 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

Definitions

  • a particle acceleration system comprising:
  • the particle beam irradiation apparatus is roughly classified into a particle beam irradiation apparatus having a synchrotron as an accelerator and a particle beam irradiation apparatus having a cyclotron as an accelerator.
  • the particle beam irradiation apparatus having a cyclotron includes, for example, an ion source, a cyclotron, a beam transport system, a rotating gantry, and an irradiation apparatus.
  • the cyclotron has a vacuum vessel composed of a pair of opposed iron cores having a circular cross section, a high-frequency accelerator, and an extraction electromagnet.
  • the beam transport system is connected to the exit of the cyclotron, where an extraction electromagnet is arranged.
  • ions emitted from an ion source for example, heavy particle ions having a mass heavier than protons such as positive ions or carbon
  • the accelerated ion beam spirally circulates from the center of the iron core toward the inner side surface of the return yoke, and is emitted to the beam transport system by an extraction electromagnet provided at the periphery of the iron core.
  • the emitted ion beam is irradiated to the affected area (cancer) of the patient on the treatment table from the irradiation device through the beam transport system.
  • the beam that circulates inside the cyclotron moves to the outer orbit as the energy increases, and is extracted outside the accelerator when it reaches the maximum energy. Accordingly, the energy of the extracted beam is generally a constant value. Therefore, in order to apply a cyclotron to particle beam therapy that requires a beam of various energies, a method of reducing the beam energy by using a degrader (energy absorber) outside the accelerator has been used.
  • a degrader energy absorber
  • the present invention has been made in view of the above-described points, and an object of the present invention is an accelerator capable of continuously extracting a beam of predetermined energy at a predetermined timing in a cyclotron accelerator, and a particle beam irradiation apparatus including the accelerator, And providing a beam extraction method.
  • the present invention includes a plurality of means for solving the above-mentioned problems.
  • the main ring-shaped coil, two iron cores that are installed opposite to each other and form a magnetic field therebetween, and a beam are provided.
  • a beam detachment device comprising a built-in coil for generating a deflection magnetic field for the purpose.
  • Embodiments of an accelerator, a particle beam irradiation apparatus, and a beam extraction method according to the present invention will be described with reference to FIGS.
  • FIG. 1 is a diagram showing the overall configuration of the particle beam irradiation apparatus of the present invention.
  • a particle beam irradiation apparatus 100 includes an accelerator 1, a beam transport system 60, an irradiation apparatus 70, a treatment table 90, and a control apparatus 80.
  • ions generated by the ion source 12 are accelerated by the accelerator 1 to form an ion beam.
  • the accelerated ion beam is emitted from the accelerator 1 and transported to the irradiation device 70 by the beam transport system 60.
  • the transported ion beam is shaped by the irradiation device 70 so as to match the shape of the affected part, and is irradiated to a target of the patient 95 lying on the treatment table 90 by a predetermined amount.
  • each device and equipment in the particle beam irradiation apparatus 100 including the accelerator 1 is controlled by the control device 80.
  • FIG. 2 shows the appearance of the accelerator according to the embodiment.
  • the accelerator 1 shown in FIG. 2 is a variable energy continuous wave accelerator capable of continuously outputting a beam with variable energy.
  • a high frequency electric field is applied to a charged particle beam that circulates in a constant magnetic field at a constant frequency (isochronous). It is a circular accelerator that accelerates.
  • the accelerator 1 is installed opposite to each other, and its outer shell is formed by a main electromagnet 11 that can be divided into upper and lower portions to form a magnetic field therebetween, and the inside is evacuated. .
  • the main electromagnet 11 has a plurality of through holes. Among them, the extracted beam through hole 111 for taking out the accelerated beam and the coil connection for drawing out the conducting wire of the internal coil 13 (see FIG. 3) to the outside.
  • a through-hole 112 and a high-frequency power input through-hole 114 are provided on the connection surface of the upper and lower main electromagnets 11.
  • An ion source 12 is installed above the main electromagnet 11, and a beam is incident on the accelerator 1 through the beam entrance through hole 115. The beam is incident at a position different from the center of gravity of the main electromagnet 11.
  • the ion source 12 may be disposed in the evacuated internal space 20 inside the main electromagnet 11.
  • FIG. 3 shows a schematic cross-sectional view of the accelerator.
  • the accelerator 1 includes a coil (main coil) 13, a return yoke 14, magnetic pole protrusions 121, 122, 123, and 124, an extraction septum electromagnet 40, and a beam extraction path (beam). (Exit path) 140, high-frequency acceleration cavities 21 and 22, and built-in coils 28 and 28A as beam detaching devices are provided.
  • a cylindrical return yoke 14 is provided outside the coil 13.
  • the magnetic pole convex portions 121, 122, 123, and 124 are formed inside the coil 13.
  • the strength of the magnetic field along the beam trajectory is added, and the average value of the magnetic field along the trajectory is made proportional to the relativistic ⁇ factor of the beam, while the orbiting time of the orbiting beam is made constant regardless of energy.
  • the betatron oscillation stably occurs in the beam orbital plane and in the direction perpendicular to the orbital plane.
  • the magnetic pole recess (valley) is provided with high-frequency acceleration cavities 21 and 22 for exciting a high-frequency electric field, and an extraction septum electromagnet 40.
  • the orbits of energy larger than 50 MeV are gathered most closely near the incident point of the extraction septum electromagnet 40.
  • An area where the orbits are densely gathered is called an aggregation area.
  • the acceleration gap is installed along an isochronous line.
  • FIG. 6 the magnetic field distribution on the center plane is shown as an isomagnetic diagram in FIG.
  • the maximum magnetic field 2.2T and the minimum magnetic field 0.86T are divided into 32 stages and expressed by isomagnetic lines.
  • the circles indicated by the broken lines in FIGS. 3, 4 and 6 are circles having a radius of 1494 mm, and the trajectory of all energy is included in the circle.
  • Fig. 7 shows the evaluation results of the betatron frequency (tune) around the orbit under the above conditions.
  • the tune was calculated based on the magnetic field gradient obtained from the magnetic field of the orbit and the energy of the front and back.
  • the horizontal tune is almost 1 at low energy and increases with acceleration. Also, it was found that the tune in the direction perpendicular to the orbital plane (vertical tune) is almost zero at low energy, and exists in the range of 0 to less than 0.5 in the entire energy region.
  • FIG. 8 shows the internal structure of the high frequency acceleration cavity 22.
  • a high frequency electric field is formed in the acceleration gaps 23 and 24 formed between the cavity outer wall 29 and the D electrode 25 by supplying high frequency power to the high frequency acceleration cavity 22 from the outside.
  • the cavity outer wall 29 is provided with a beam through hole in the vicinity of the acceleration gaps 23 and 24 (not shown).
  • the beam is accelerated by passing through the acceleration gaps 23, 24 with an appropriate high-frequency electric field phase.
  • the Dee electrode 25 is supported by hollow cylindrical stems 26 and 27.
  • the high frequency acceleration cavity 22 has a vertically symmetrical structure with respect to the beam trajectory plane.
  • FIG. 9 is a cross-sectional view of the high-frequency accelerating cavity 22 as viewed from the beam trajectory surface on the D electrode 25 side.
  • a built-in coil 28 is disposed in the dee electrode 25, and is connected to the dee electrode 25 via an insulator.
  • FIG. 10 shows a cross-sectional view along B-B ′ of FIG.
  • the lead wire 30 of each coil 28a, 28c, 28e, 28g, 28i,... Of the built-in coil 28 is led to the outside of the high frequency acceleration cavity 22 through the inside of the stems 26, 27, and is connected to a power source and a water cooling device. . Since the hollow conductor forming the built-in coil 28 is cooled by the cooling water flowing therein, not only the heat generated by the built-in coil 28 itself but also the heat generated by the Dee electrode 25 can be cooled.
  • a plurality of current paths (coils 28b, 28d, 28f, 28h, 28j,...) Formed using hollow conductors inside the dee electrode 25 are also beamed inside the high-frequency acceleration cavity 21.
  • a built-in coil 28A installed in a direction substantially parallel to the track is disposed.
  • the polarity of the deflection magnetic field generated by the built-in coil 28 ⁇ / b> A disposed in the high-frequency acceleration cavity 21 is reversed to the polarity of the deflection magnetic field generated by the built-in coil 28 disposed in the high-frequency acceleration cavity 22.
  • the lead wire 30 of each of the coils 28b, 28d, 28f, 28h, 28j,... Of the built-in coil 28A is also led to the outside of the high-frequency acceleration cavity 21 through the stems 26, 27, and a power source and a water cooling device (both not shown) )It is connected to the.
  • the hollow conductor forming the built-in coil 28A can also cool the heat generated by the built-in coil 28A and the Dee electrode 25 at the same time by water cooling the inside.
  • the beam trajectory of the corresponding energy may be bilaterally symmetrical, the coil 28c and the coil 28b, the coil 28e and the coil 28d, It is also possible for the coil 28g and the coil 28f to be left-right asymmetric with the coils 28i and 28h shifted one by one so as to correspond to each other.
  • the built-in coils 28 and 28A have an air-core structure so as not to disturb the main magnetic field distribution.
  • the rise time of the deflection magnetic field 31 can be shortened compared with the case where an iron core is inserted, so that high speed such as scanning irradiation is possible. Suitable for cases where energy switching is required.
  • a slit 25 a as shown in FIG. 3 can be provided on the surface of the Dee electrode 25 in the radial direction of the accelerator 1. At least one slit 25 a can be provided on the surface of the dee electrode 25.
  • the high-frequency filter 33 can be a very general low-pass filter configured by a series inductor or a combination of a series inductor and a parallel capacitor.
  • the particle beam irradiation apparatus 100 of the present embodiment described above includes the accelerator 1 and the irradiation apparatus 70 that irradiates the beam emitted from the accelerator 1, and the accelerator 1 is opposed to the annular coil 13.
  • Two main electromagnets 11 that form a magnetic field therebetween, high-frequency accelerating cavities 21 and 22 and a dee electrode 25 for accelerating the beam, a beam extraction path 140 for extracting the beam to the outside, and a dee electrode 25
  • a beam detachment device including built-in coils 28 and 28A for generating a deflection magnetic field for detaching the beam from the beam orbit and guiding it to the beam extraction path 140 at a plurality of positions in the radial direction of the coil 13. Is. Then, at least one type of energy beam is extracted from the accelerator 1.
  • a beam of predetermined energy can be continuously extracted by the deflection magnetic field generated by the built-in coils 28 and 28A disposed in the dee electrode 25 in the high-frequency acceleration cavities 21 and 22. Therefore, a beam having a predetermined energy can be continuously obtained without providing an extra configuration such as a degrader on the beam trajectory. Therefore, the accelerator 1 without problems such as a decrease in beam utilization efficiency, an increase in beam size, an increase in unnecessary secondary particles, and an increase in the size of the accelerator 1 can be obtained.
  • the high-frequency acceleration cavities 21 and 22 have both the functions of accelerating and extracting the beam, it also contributes to the space saving of the accelerator 1.
  • the accelerator used in this method is the same as the conventional AVF cyclotron in that it has a concavo-convex shaped main electromagnet magnetic pole, but the ion incident part position is shifted from the central axis of the accelerator to decenter the trajectory, and a plurality of different energy
  • the main magnetic field distribution is adjusted so that the beam orbit converges at the entrance of the beam emission path.
  • a deflection electromagnet device is installed as a beam detachment device in the main electromagnet magnetic pole recess (valley) located 180 degrees opposite to the entrance of the beam emission path, and the deflection magnetic field is controlled so as to act only on the beam trajectory of a specific energy. Yes.
  • the betatron frequency (horizontal tune) in the direction parallel to the beam trajectory plane is a value close to 1 particularly in the low energy region. Even if the beam is perturbed at a position on the opposite side, the horizontal movement amount of the beam is maximized at a position approximately 90 degrees before the entrance of the beam emission path. Therefore, since it cannot be taken out at a position where the maximum amount of movement can be obtained, there is a problem that an extra magnetic field strength of the deflection electromagnet is required.
  • the deflection magnet for beam extraction needs to be installed in a narrow gap between the main electromagnet magnetic poles, it is difficult to increase the size and the magnetic field strength tends to be insufficient. For this reason, it is difficult to take out the beam in half a circle after operating the deflection electromagnet.
  • a deflecting electromagnet for beam extraction is installed in one place, the isochronous condition is lost due to the deflecting magnetic field. There is a grudge that it will be difficult to obtain.
  • a beam having a predetermined energy is taken out by the built-in coils 28 and 28A arranged in the dee electrode 25 in the high-frequency acceleration cavities 21 and 22, so that a deflecting magnetic field coil having a small magnetomotive force is used.
  • the intensity of the deflection magnetic field for extraction can be kept low, and a beam having a wide range of energy can be continuously extracted with high efficiency while satisfying the isochronous condition.
  • the built-in coils 28 and 28A are massless septum electromagnets using air-core wires, the rise time of the deflection magnetic field 31 can be made shorter than when the iron core is inserted without disturbing the main magnetic field distribution.
  • an accelerator suitable for a particle beam irradiation apparatus that requires high-speed energy switching such as scanning irradiation.
  • the inside can be cooled with water, not only the heat generation of the built-in coil 28 itself but also the heat generation of the Dee electrode 25 can be cooled, and efficient cooling becomes possible.
  • a plurality of built-in coils 28, 28 A are installed inside the D electrode 25, and the lead wires 30 of the built-in coils 28, 28 A are guided to the outside of the high-frequency acceleration cavities 22, 21 through the inside of the stems 26, 27 that support the D electrode 25.
  • a beam having a predetermined energy can be extracted continuously and efficiently more easily without providing an extra structure such as a degrader on the beam trajectory while saving space.
  • the high-frequency acceleration cavity and the entrance of the beam emission path are generally arranged in a magnetic pole recess (valley) with a sufficient space. Therefore, the high-frequency acceleration cavities 21 and 22 are arranged symmetrically by arranging the high-frequency acceleration cavities 22 and 21 etc. at positions 90 degrees ahead and 90 degrees along the beam traveling direction from the entrance of the beam extraction path 140, The circular beam can be kicked, and the beam can be taken out at a position where the maximum amount of beam movement can be obtained when the horizontal tune is close to 1. Therefore, the beam can be extracted more efficiently even with a smaller deflection magnetic field strength.
  • the Dee electrode 25 is provided with a slit 25a in the radial direction of the coil 13, even if an eddy current is generated on the surface of the Dee electrode 25, this can be interrupted. Even if the rise time of the energized current is shortened, it is possible to suppress a delay in the response of the deflection magnetic field 31.
  • the amount of high-frequency current leaking to the outside of the high-frequency acceleration cavities 21 and 22 through the built-in coils 28 and 28A can be reduced. It can be further reduced.
  • the beam separation device is disposed in the high-frequency acceleration cavities 21 and 22 for accelerating the beam
  • the beam separation device can be further disposed in the accelerator 1.
  • a massless septum electromagnet can be further arranged in the magnetic pole concave portion between the magnetic pole convex portion 122 and the magnetic pole convex portion 123, and a massless septum electromagnet can be arranged in another location.
  • Particle beam irradiation device 111 Extraction beam through-hole 112 ... Coil connection through-hole 114 ... High-frequency power input through-hole 115 ... Beam entrance through-holes 121, 122, 123, 124 ... Magnetic pole projections 130 ... Incident point 140: Beam extraction path (beam output path)

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  • Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
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  • High Energy & Nuclear Physics (AREA)
  • Particle Accelerators (AREA)
  • Radiation-Therapy Devices (AREA)

Abstract

La présente invention comprend : une bobine annulaire (13) ; deux électroaimants principaux (11) installés en regard l'un de l'autre et formant un champ magnétique entre eux ; des cavités d'accélération haute fréquence (21, 22) et une électrode dé (25) qui accélèrent un faisceau ; un chemin d'extraction de faisceau (140) par lequel le faisceau est extrait vers l'extérieur ; et un dispositif de déviation de faisceau disposé dans l'électrode dé (25) et constitué de bobines intégrées (28, 28A) qui génèrent un champ magnétique de déviation de façon à guider le faisceau vers le trajet d'extraction de faisceau (140) par déviation du faisceau d'une orbite de circulation en de multiples emplacements dans la direction radiale de la bobine (13). Ainsi, la présente invention porte sur un accélérateur qui peut extraire en continu, dans un accélérateur de cyclotron, un faisceau d'une énergie prédéfinie à un moment prédéfini, sur un dispositif d'exposition de faisceau de particules pourvu d'un tel accélérateur et sur un procédé d'extraction du faisceau.
PCT/JP2017/037387 2016-11-18 2017-10-16 Accélérateur, dispositif d'exposition à un faisceau de particules et procédé d'extraction de faisceau Ceased WO2018092483A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016224683A JP2020030882A (ja) 2016-11-18 2016-11-18 加速器および粒子線照射装置、ならびにビームの取出し方法
JP2016-224683 2016-11-18

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113365408A (zh) * 2021-05-20 2021-09-07 中国原子能科学研究院 一种加速结构及多腔加速器

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010287419A (ja) * 2009-06-11 2010-12-24 Sumitomo Heavy Ind Ltd 粒子加速システム
WO2016092622A1 (fr) * 2014-12-08 2016-06-16 株式会社日立製作所 Accélérateur, et dispositif de rayonnement de faisceau de particules

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010287419A (ja) * 2009-06-11 2010-12-24 Sumitomo Heavy Ind Ltd 粒子加速システム
WO2016092622A1 (fr) * 2014-12-08 2016-06-16 株式会社日立製作所 Accélérateur, et dispositif de rayonnement de faisceau de particules

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113365408A (zh) * 2021-05-20 2021-09-07 中国原子能科学研究院 一种加速结构及多腔加速器

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