Proton helium ion treatment device based on synchrotron

Abstract

The invention relates to a proton helium ion treatment device based on a synchrotron, an ion source system respectively generates # imgabs0 # and helium ions through two electron cyclotron resonance ion sources, an injector comprises a four-wing RFQ and an IH-DTL, # imgabs1 # or helium ions are preliminarily accelerated to 8MeV / u through the four-wing RFQ and the IH-DTL, # imgabs2 # is stripped into protons through a stripper, and # imgabs3 # or helium ions are stripped into protons through the four-wing RFQ and the IH-DTL. Protons or helium ions are injected into the synchrotron through the injection system, the synchrotron accelerates the protons or helium ions to 235 MeV / u and then the protons or helium ions are led out of the synchrotron through the leading-out system, and the led-out protons or helium ions enter a treatment room for treatment after the transverse size of the protons or helium ions is made to be smaller than 10 mm through the beam transmission system. According to the proton helium ion treatment device, miniaturization of the treatment device is achieved, popularization of helium ion treatment is finally achieved, and the proton helium ion treatment device is welfare for livelihood.

Description

Technical Field

[0001] The present invention relates to particle therapy, and more particularly to a proton helium ion therapy device based on a synchrotron. Background Art

[0002] Proton and heavy ion therapy is an important means of treating cancer and is widely used clinically. Thanks to the dose distribution characteristics of the Bragg peak, it can accurately locate the location of tumor cells, while eliminating tumor cells, protecting healthy tissues and organs of the human body. Different types of particles have different biological effects, and the depth of the Bragg peak is also different, so the applicable tumor types are also different.

[0003] The type of particles commonly used in cancer treatment is protons (H + ) and carbon ions (C 6+ ). Protons can locate tumors more accurately, but their biological effects are weaker, and multiple irradiations are often required to complete the entire treatment; while carbon ions can kill tumor cells quickly, but the irradiated penumbra is larger, causing greater damage to healthy tissues and organs in the human body. Based on the study of different particles, it was found that helium ions (He 2+ ) has the characteristics of high biological effect and small penumbra zone, and is expected to achieve better results in treatment.

[0004] Since the concept of particle beam therapy was proposed, the Lawrence Berkeley National Laboratory (LBL) in the United States has begun related research and experiments, including a variety of ions and tumors in different parts, among which helium ion therapy began in 1957. With the shutdown of the accelerator at LBL in 1992, the research progress of different particles in tumor treatment began to show huge differences. Due to various historical reasons, protons and carbon ions are the fastest-growing, until helium ion therapy has regained attention in recent years. At present, there are only two medical accelerators in the world that can be used to accelerate helium ions, one in Japan HIMAC (Heavy Ion Medical Accelerator in Chiba) and one in Germany HIT (Heidelberg IonBeam Therapy Center). HIMAC's accelerator is designed to accelerate helium ions to argon ions, but the actual helium ions are only used to calibrate the machine and are not used for treatment. HIT's accelerator was originally designed to use protons and carbon ions, but was later upgraded to add helium ions, and helium ions were applied to clinical practice in 2021. In short, helium ion therapy is still in the experimental stage. There are no commercial devices that utilize helium ions, let alone dedicated helium ion accelerators and treatment centers. Summary of the invention

[0005] In order to solve the problem that there is no commercial device using helium ions in the prior art, the present invention provides a proton helium ion therapy device based on a synchrotron.

[0006] The synchrotron-based proton helium ion therapy device of the present invention comprises an ion source system, an injector, an injection system, a synchrotron accelerator, an extraction system, a beam transmission system and a treatment room, wherein the ion source system generates two electron cyclotron resonance ion sources respectively. and helium ions, implanters include quad-wing RFQ and IH-DTL, Or helium ions are initially accelerated to 8MeV / u by a four-wing RFQ and IH-DTL, After being stripped into protons by the stripper, the protons or helium ions are injected into the synchrotron through the injection system. The synchrotron accelerates the protons or helium ions to 235MeV / u and then extracts them from the synchrotron through the extraction system. The extracted protons or helium ions pass through the beam transmission system to make their lateral size less than 10mm and then enter the treatment room for treatment.

[0007] In a preferred embodiment, the operating frequency of the four-wing RFQ is 425 MHz.

[0008] In a preferred embodiment, the injector is designed based on a particle charge-to-mass ratio of 1 / 2 to facilitate simultaneous acceleration and helium ions.

[0009] In a preferred embodiment, the injector further comprises a medium energy transmission line, on which a stripper is arranged to Stripped to protons.

[0010] In a preferred embodiment, the synchrotron accelerates protons to 235 MeV to 750 MeV.

[0011] In a preferred embodiment, the treatment room is equipped with proton CT in conjunction with proton helium ion therapy.

[0012] In a preferred embodiment, the circumference of the synchrotron is less than 28 meters, thereby achieving miniaturization. It should be understood that although the synchrotron for therapeutic devices has been developed for decades and the technology is relatively mature, the only synchrotrons dedicated to treatment in the world are designed for protons and carbon ions. Although the carbon ion synchrotron can theoretically accelerate helium ions and protons, the radius of the carbon ion synchrotron is much larger than that of the proton and helium ion synchrotrons under the same technical conditions, that is, research on miniaturized helium ion synchrotrons has not yet been carried out.

[0013] In a preferred embodiment, the synchrotron includes eight dipole magnets, and synchronization is achieved by controlling the magnet power supply so that the strength of the dipole magnets varies with the beam energy.

[0014] In a preferred embodiment, the treatment room includes a fixed beam treatment room and / or a rotating beam treatment room. In the fixed beam treatment room, the direction of the beam does not change and the affected area is irradiated at a fixed angle; in the rotating beam treatment room, the direction of the beam changes according to the treatment needs and the affected area is irradiated at multiple angles.

[0015] In a preferred embodiment, the beam delivery system comprises a rotating gantry extending into the rotating beam treatment room, and the dipole magnet on the rotating gantry is a superconducting dipole magnet.

[0016] The synchrotron-based proton helium ion therapy device of the present invention focuses on helium ions and is compatible with protons, thereby realizing miniaturization of the therapy device. The volume of the synchrotron and the rotating therapy head part is significantly smaller than that of the existing carbon ion therapy device, thereby reducing the volume and construction cost of the therapy device. The advantages of helium ion therapy can be fully utilized, the effect of particle beam therapy can be improved, and ultimately the promotion of helium ion therapy can be realized, thereby bringing benefits to people's livelihood. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of a synchrotron-based proton helium ion therapy device according to a preferred embodiment of the present invention.

[0018] Figure 2 yes Figure 1 Top view of the . DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0020] like Figure 1-Figure 2 As shown, according to a preferred embodiment of the present invention, a synchrotron-based proton helium ion therapy device A comprises an ion source system 1, an injector 2, an injection system 3, a synchrotron 4, an extraction system 5, a beam transport system 6 and a treatment room 7, wherein the ion source system 1 generates and helium ions He 2+ The beam is initially accelerated to 8 MeV / u by injector 2. After being stripped by the stripper, it is stripped into protons p, protons p or helium ions He 2+ The synchrotron 4 injects protons p or helium ions He into the synchrotron 4 through the injection system 3. 2+ After being accelerated to 235 MeV / u, it is extracted from the synchrotron 4 through the extraction system 5. The extracted protons p or helium ions He 2+ The beam passes through the beam transport system 6 and enters the treatment room 7 for treatment.

[0021] The ion source system 1 is the source of the entire device, generating a charged particle (ion) beam, including two electron cyclotron resonance (ECR) ion sources 1, which are used to generate H2 + and 4 He 2+ The basic principle of the ion source 1 is to introduce gas into the cavity and turn the gas into plasma by ionization (i.e., introducing hydrogen to generate Helium is introduced to produce He 2+ ), and then use the extraction high voltage to increase the speed of the corresponding particles to a certain extent and extract them. The microwaves and pores of the ion source 1 realize the generation and stopping of the particle beam, as well as the switching of the two particles through the control system. The ion source system 1 also includes a low-energy transmission section (Low Energy Beam Transport, LEBT), which can transmit the beam, change the direction, and focus the beam so that the beam meets the acceptance requirements of the injector 2. Specifically, the low-energy transmission line is mainly composed of a solenoid, a dipole magnet, a quadrupole magnet, a beam cutter, etc., wherein the solenoid and the quadrupole magnet are used for beam focusing, the dipole magnet is used to change the direction of the beam to meet the layout requirements of the device, and the beam cutter is used to control the passage of the beam. In this way, after focusing, screening and transmission by the low-energy transmission line, the particle beam is transmitted to the beam track with parameters acceptable to the injector 2, and impurities in the particle beam are removed.

[0022] Among them, the injector 2 is an accelerator immediately after the ion source system 1, which is used to initially accelerate the beam and pre-accelerate the particles generated by the ion source so that the beam meets the injection requirements of the synchrotron. Protons and helium ions at low energy have the characteristics of slow speed and strong space charge effect. Such a beam is unacceptable to the synchrotron 4, so the injector 2 is required to increase the beam energy to a level suitable for the synchrotron 4. The injector 2 has a quadrupole magnet, a buncher and a beam spreader to match the beam parameters to ensure that the beam can be effectively accelerated in the injector 2 and enter the synchrotron 4 through the injection system 3 with appropriate parameters. The injector 2 is designed according to the particle charge-to-mass ratio of 1 / 2, which can accelerate H2 at the same time. + and He 2+ , the outlet energy is above 8MeV / u. Figure 1As shown, the helium ion therapy device also includes a medical isotope preparation 10, which is connected to the injection system 3 as an option. The outlet energy selection of the injector 2 can be applied to the production of medical isotopes and achieve a higher yield. Specifically, the injector 2 is composed of a radio frequency quadrupole accelerator (RFQ), a drift tube linear accelerator (DTL) and a medium energy transmission line arranged in sequence. RFQ is an acceleration structure invented for the characteristics of proton beams at low energy. It is mainly composed of four electrodes to produce a strong focusing effect, which solves the problem of the increase in the emittance of proton beams at low energy. At the same time, modulation is added to the pole head to produce an acceleration effect. In the present invention, the RFQ is a four-wing type, and the electrodes of the four-wing type RFQ are directly connected to the cavity wall. The positive and negative voltages are realized through the circumferential phase difference. The four electrodes produce a strong focusing effect, which solves the problem of the increase in the emittance of proton beams at low energy. At the same time, modulation is added to the pole head to produce an acceleration effect. The four-wing RFQ can be applied to higher frequencies. Furthermore, the high-frequency four-wing RFQ has a smaller volume. Specifically, the four-wing RFQ is used for frequencies above 200 MHz. Its pole head forms a "wing-like" structure. The heat accumulated at the pole tip can be transferred to the wing and dissipated through the water-cooling pipe of the wing. The higher the frequency of the four-wing RFQ, the smaller its size. The operating frequency of the RFQ of the injector 2 of the helium ion therapy device A according to the present invention is 425 MHz, which is higher than the frequency of the existing heavy ion RFQ, so the size is smaller, thereby achieving a higher acceleration gradient through a compact design and shortening the length of the injector part. The difficulty lies in that the focusing intensity of the RFQ is inversely proportional to the frequency. The higher the frequency, the lower the focusing intensity, the greater the probability of beam loss during the acceleration process, that is, the transmission efficiency decreases. The RFQ in the present invention uses a special design method of variable focusing intensity and variable beam aperture, and also achieves high transmission efficiency at higher frequencies. DTL is an accelerator structure composed of a drift tube and an acceleration gap. When the proton velocity β~0.1, DTL is the most suitable accelerator type. The traditional DTL type, i.e., Alvarez type DTL, has a low acceleration gradient, a long acceleration length for the same energy, and this type of DTL requires the addition of permanent magnetic quadrupole iron in the drift tube, which has a large process difficulty, and the error that may be generated is also large, and it is difficult to adjust after the processing is completed. In the present invention, the DTL is an IH-DTL designed by KONUS beam dynamics, which can achieve a higher acceleration gradient and greatly reduce the length of the DTL. At the same time, the magnet does not need to be installed in the drift tube, which reduces the process difficulty, and has a wider range of magnet selection, and electromagnetic quadrupole iron can be selected, and can be adjusted for errors during actual debugging and operation. The difficulty lies in the relatively weak focusing effect.The energy of heavy ions is very low in the injector stage, the space charge effect is large, and they are more likely to diverge during the acceleration process. Therefore, the structural design of IH-DTL needs to be more carefully optimized to achieve better beam quality and high transmission efficiency. The medium-energy transmission line mainly includes a quadrupole magnet and a buncher, which are used to adjust the beam parameters from the upstream accelerator to meet the acceptance requirements of the downstream accelerator. In the present invention, a beam stripper is provided on the medium-energy transmission line to remove H2. + Stripped to proton p.

[0023] The role of the injection system 3 is to match the beam trajectory and inject the beam into the synchrotron 4. The injector 2 is a linear accelerator with a linear beam trajectory, while the synchrotron 4 is a circular accelerator with a circular beam trajectory, so the beam cannot directly enter the synchrotron 4. The injection system 3 deflects the particle beam to the appropriate direction through a combination of dipole magnets, and realizes the transformation of the beam trajectory through devices such as a beam kicker and a cutting plate.

[0024] Among them, the synchrotron 4 is a circular accelerator that accelerates the beam to the required energy. The magnet strength in the accelerator increases with the increase of particle beam energy to form synchronization. The synchrotron 4 realizes the synchronous change of magnetic field strength and magnetic field gradient with the increase of particle beam energy through the combination of dipole magnets and quadrupole magnets, combined with a control system. The synchrotron 4 uses eight dipole magnets, and the overall appearance is an octagon. The strength of the dipole magnets changes with the change of beam energy, which is achieved by controlling the magnet power supply. From the perspective of details, the synchrotron involved in the present invention is also improved and different from the existing medical synchrotron. The synchrotron 4 is mainly designed based on the indicators of helium ions, with a circumference of less than 28 meters, to achieve the miniaturization of the accelerator, and at the same time, the acceleration of protons can be achieved by controlling the magnets. The synchrotron 4 can accelerate p and He at the same time. 2+ , which can accelerate protons p to 235 MeV and helium ions He 2+ Accelerated to 235MeV / u. The energy of protons can be accelerated to a higher level, up to 750MeV, which can meet the needs of proton CT.

[0025] The extraction system 5 is used to match the beam trajectory and extract the beam from the synchrotron 4. The extraction system 5 uses a combination of a dipole magnet and a cutting plate to extract the particle beam in an orderly manner in accordance with the resonance theory and arrive at the subsequent linear trajectory of the beam. The extraction system 5 can simultaneously apply p and He with different energies. 2+ The extraction system 5 is a slow extraction, and the slow extraction at the 2 / 3 resonance point is optimal, meeting the requirements of helium ion therapy for beam parameters.

[0026] The beam transmission system 6 is a device for transporting and matching the beam, transmitting the beam to the treatment room 7 and matching it to the accuracy and size required for treatment to meet the requirements of the beam cross-sectional size for tumor treatment. In the proton helium ion treatment device A, at least two treatment rooms 7 are equipped. The beam parameters drawn by the synchrotron 4 do not meet the treatment requirements and cannot be used directly for treatment. Instead, they are transmitted to the treatment room 7 through the beam transmission system 6. The beam transmission system 6 includes a beam transmission system for p and He 2+ Optimized high-energy transmission line. Specifically, the beam transmission system 6 is composed of a dipole magnet, a quadrupole magnet, a correction magnet, etc., which are used to change the beam path, focus, and correct the beam position, respectively, to achieve changes in the beam trajectory and control of the beam parameters. After passing through the beam transmission system 6, the lateral size of the beam is less than 10 mm, meeting the needs of treatment.

[0027] Among them, the treatment room 7 includes a fixed beam treatment room 71 or a rotating beam treatment room 72. In the fixed beam treatment room 71, the direction of the beam will not change, and the affected part is irradiated at a fixed angle. The beam transmission system 6 in the fixed beam treatment room 71 ensures that the beam reaches the affected part with accuracy that meets the treatment requirements. In the rotating beam treatment room 72, the direction of the beam can be changed according to the treatment requirements, and the affected part is irradiated at multiple angles. The beam transmission system 6 includes a rotating gantry 61, which is a rotatable mechanical support structure arranged in the rotating beam treatment room 72 to achieve angle changes, thereby achieving treatment requirements through the rotating gantry 61. In the rotating beam treatment room 72, the dipole magnet on the rotating gantry 61 uses a superconducting dipole magnet, whose field strength can reach 4T, which can reduce the volume of the rotating gantry 61. The size of the rotating gantry 61 is mainly affected by the bending radius of the dipole magnet. The heavy ion magnetic stiffness is relatively high, and the superconducting dipole magnet can achieve a higher magnetic field strength, reduce the bending radius, and realize the miniaturization of the rotating gantry.

[0028] The treatment room 7 includes a treatment system, which includes a treatment head, a treatment bed, a positioning system, a respiratory gating system, a treatment control system, etc., so as to achieve the final treatment in the treatment room and better meet the needs of tumor patients for the diversity of particle beam treatment. The treatment head can deflect the beam to achieve scanning irradiation of the affected area. The treatment head is used for He 2+ The treatment bed is used to fix the patient and cooperate with the treatment head to achieve irradiation at different angles in the treatment plan. The positioning system is used to locate the patient and the affected area to ensure the accuracy of the treatment. Respiratory gating can monitor the patient's respiratory movement and cooperate with the treatment head to adjust the treatment depth in real time to reduce the damage of irradiation to healthy tissues and cells of the human body. The treatment control system is the medium for medical staff to operate various treatment equipment. In particular, treatment room 7 is equipped with a proton CT, which is more accurate in positioning when combined with proton helium ion therapy.

[0029] According to the proton helium ion therapy device A of the present invention, the maximum energy required for the helium ions used for treatment is 235MeV / u, which is much lower than the energy required for carbon ion therapy. Therefore, under the same conditions, the equipment required for helium ion therapy (mainly including accelerators, racks and treatment heads) is smaller in size and lower in cost. At the same time, the helium ion device can also be compatible with protons to provide a variety of particles for treatment. Preferably, according to the proton helium ion therapy device A of the present invention, the injector adopts a combination of a four-wing RFQ and an IH-DTL, wherein IH-DTL has not been applied to a heavy ion (generally referring to ions with a mass greater than proton) therapy device; the magnet technology used in the synchrotron can effectively reduce the circumference of the synchrotron; the injection extraction system can better cope with the extraction requirements of heavy ions at different energies through variable electrode spacing and cutting plate deflection angles; the beam transmission system can not only ensure the basic requirements of beam distribution to different treatment rooms, but also improve the stability of the system; in the rotating beam treatment room, because the beam transmission system uses superconducting magnets, the size of the rotating rack is smaller than the existing heavy ion treatment rotating rack; in the treatment room, a proton CT can also be equipped to improve the accuracy of positioning.

[0030] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A synchrotron-based proton helium ion therapy device, characterized in that: The proton helium ion therapy device comprises an ion source system, an injector, an injection system, a synchrotron accelerator, an extraction system, a beam transmission system and a treatment room, wherein the ion source system generates two electron cyclotron resonance ion sources respectively. and helium ions, implanters include quad-wing RFQ and IH-DTL, Or helium ions are initially accelerated to 8MeV / u by a four-wing RFQ and IH-DTL, After being stripped into protons by the stripper, the protons or helium ions are injected into the synchrotron through the injection system. The synchrotron accelerates the protons or helium ions to 235MeV / u and then extracts them from the synchrotron through the extraction system. The extracted protons or helium ions pass through the beam transmission system to make their lateral size less than 10mm and then enter the treatment room for treatment.

2. The proton helium ion therapy device according to claim 1, characterized in that: The operating frequency of the four-wing RFQ is 425MHz.

3. The proton helium ion therapy device according to claim 1, characterized in that: The injector is designed based on a particle charge-to-mass ratio of 1 / 2 to facilitate simultaneous acceleration and helium ions.

4. The proton helium ion therapy device according to claim 1, characterized in that: The injector also includes a medium energy transmission line, on which a stripper is provided to Stripped to protons.

5. The proton helium ion therapy device according to claim 4, characterized in that: The synchrotron accelerates protons to 235MeV ~ 750MeV.

6. The proton helium ion therapy device according to claim 5, characterized in that: The treatment room is equipped with proton CT and proton helium ion therapy.

7. The proton helium ion therapy device according to claim 1, characterized in that: The circumference of the synchrotron is less than 28 meters.

8. The proton helium ion therapy device according to claim 1, characterized in that: The synchrotron accelerator includes eight dipole magnets. By controlling the magnet power supply, the strength of the dipole magnets changes with the beam energy to achieve synchronization.

9. The proton helium ion therapy device according to claim 1, characterized in that: The treatment room includes a fixed beam treatment room and / or a rotating beam treatment room. In a fixed beam treatment room, the direction of the beam does not change and the affected area is irradiated at a fixed angle; in a rotating beam treatment room, the direction of the beam changes according to treatment needs and the affected area is irradiated at multiple angles.

10. The proton helium ion therapy device according to claim 9, characterized in that: The beam transmission system comprises a rotating gantry extending into the rotating beam treatment room, and the dipole magnet on the rotating gantry is a superconducting dipole magnet.

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