Proton and helium ion therapeutic device based on synchrotron

Abstract

Provided is a proton and helium ion therapeutic device (A) based on a synchrotron (4). An ion source system (1) separately generates H 2 + and helium ions by means of two electron cyclotron resonance ion sources. An injector (2) comprises a four-vane RFQ and IH-DTL. H 2 + or helium ions are preliminarily accelerated to 8 MeV / u by means of the four-vane RFQ and IH-DTL, and then stripped into protons by means of a stripper. The protons or helium ions are injected into the synchrotron (4) by an injection system (3), accelerated to 235 MeV / u in the synchrotron (4), and then extracted from the synchrotron (4) by an extraction system (5). The extracted protons or helium ions pass through a beam transmission system (6) to make the transverse size thereof less than 10 mm, and then enter a treatment room (7) for treatment.

Description

A proton-helium ion therapy device based on a synchrotron Technical Field

[0001] This invention relates to particle therapy, and more specifically to a proton-helium ion therapy device based on a synchrotron. Background Technology

[0002] Proton and heavy ion therapy is an important and widely used method for treating cancer. It benefits from the dose distribution characteristics of the Bragg peak, allowing for precise location of tumor cells and the elimination of tumor cells while protecting healthy tissues and organs. Different types of particles have different biological effects, and the depth of the Bragg peak also varies, thus making them suitable for different types of tumors.

[0003] Currently, the most commonly used particle type in cancer treatment is the proton (H). + ) and carbon ions (C 6+ Protons can pinpoint tumor locations more precisely, but their biological effects are weaker, often requiring multiple irradiations to complete the treatment. Carbon ions, on the other hand, can rapidly kill tumor cells, but their larger penumbra results in greater damage to healthy tissues and organs. Based on research on different particles, helium ions (He...) have been found... 2+ It also has the characteristics of high biological efficacy and small penumbra area, which is expected to achieve better results in treatment.

[0004] Since the concept of particle beam therapy was proposed, Lawrence Berkeley National Laboratory (LBL) in the United States has begun related research and experiments, including on various ions and tumors in different locations. Helium ion therapy began in 1957. With the shutdown of LBL's accelerator in 1992, the research progress of different particles in tumor treatment began to diverge significantly. Due to various historical reasons, protons and carbon ions saw the fastest development, until recently when helium ion therapy regained attention. Currently, there are only two medical accelerators in the world that can accelerate helium ions: one at HIMAC (Heavy Ion Medical Accelerator in Chiba) in Japan, and the other at HIT (Heidelberg Ion Beam Therapy Center) in Germany. HIMAC's accelerator is designed to accelerate helium ions to argon ions, but in practice, helium ions are only used for machine calibration and not for treatment. HIT's accelerator was originally designed to use protons and carbon ions, but after upgrades, helium ions were added, and in 2021, helium ion therapy was applied clinically. 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] To address the problem of the lack of commercially available devices utilizing helium ions in the prior art, this invention provides a proton-helium ion therapy device based on a synchrotron.

[0006] The proton-helium ion therapy device based on a synchrotron according to the present invention includes an ion source system, an injector, an injection system, a synchrotron, an extraction system, a beam transport system, and a treatment chamber. The ion source system generates ion energy through two electron cyclotron resonance ion sources. Helium ions, and injectors include quad-wing RFQ and IH-DTL. Alternatively, helium ions can be initially accelerated to 8 MeV / u using a quad-wing RFQ and IH-DTL. After being stripped into protons by a stripper, the protons or helium ions are injected into the synchrotron via an injection system. The synchrotron accelerates the protons or helium ions to 235 MeV / u and then extracts them from the synchrotron via an extraction system. The extracted protons or helium ions are then transported through a beam transmission system to make their lateral dimensions less than 10 mm before entering the treatment room for treatment.

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

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

[0009] In a preferred embodiment, the injector further includes a medium-energy transmission line, on which a stripper is disposed to... It is stripped into 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 a proton CT scanner, which is used in conjunction with proton-helium ion therapy.

[0012] In a preferred embodiment, the synchrotron's circumference is less than 28 meters, thus achieving miniaturization. It should be understood that although synchrotrons for therapeutic devices have been developed over several decades and the technology is relatively mature, currently, the world's therapeutic synchrotrons are only designed for protons and carbon ions. While carbon ion synchrotrons can theoretically accelerate helium ions and protons, under equivalent technological conditions, the radius of a carbon ion synchrotron is much larger than that of a proton or helium ion synchrotron. In other words, research on miniaturized helium ion synchrotrons has not yet been conducted.

[0013] In a preferred embodiment, the synchrotron includes eight dipole magnets, and synchronization is achieved by controlling the magnet power supply so that the intensity 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 to irradiate the affected area at multiple angles.

[0015] In a preferred embodiment, the beam delivery system includes a rotating gantry extending into the rotating beam therapy chamber, wherein the diode magnets on the rotating gantry are superconducting diode magnets.

[0016] The proton-helium ion therapy device based on a synchrotron according to the present invention focuses on helium ions while being compatible with protons, thereby miniaturizing the therapy device. The volume of the synchrotron and rotating treatment head is significantly smaller than that of existing carbon ion therapy devices, reducing the size and construction cost of the therapy device. It can fully utilize the advantages of helium ion therapy, improve the effect of particle beam therapy, and ultimately promote the application of helium ion therapy, bringing benefits to people's livelihoods. Attached Figure Description

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

[0018] Figure 2 is a top view of Figure 1. Detailed Implementation

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

[0020] As shown in Figures 1-2, a synchrotron-based proton-helium ion therapy device A according to a preferred embodiment of the present invention includes 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 chamber 7. 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 a stripper, it is separated into protons (Pp) or helium ions (He). 2+ The protons (P) or helium ions (He) are injected into the synchrotron 4 via injection system 3. Synchrotron 4 then injects them into the synchrotron 4. 2+ After being accelerated to 235 MeV / u, the protons or helium ions (He) are extracted from synchrotron 4 via extraction system 5. 2+ The beam enters the treatment room 7 through the beam transmission system 6 for treatment.

[0021] The ion source system 1 is the source of the entire device, generating a beam of charged particles (ions). It includes two electron cyclotron resonance (ECR) ion sources 1, each used to generate a sufficient flux. and 4 He 2+ The basic principle of ion source 1 is to introduce gas into the cavity and ionize it into plasma (i.e., to generate plasma by introducing hydrogen gas). Helium gas is introduced to produce He 2+ The ion source 1 uses microwaves and air vents to generate and stop the particle beam, as well as switch between two types of particles, through a control system. Ion source system 1 also includes a low-energy beam transport (LEBT) section, which can transmit the beam, change its direction, and focus it to meet the acceptability requirements of injector 2. Specifically, the LEBT mainly consists of a solenoid, a diode magnet, a quadrupole magnet, and a beam cutter. The solenoid and quadrupole magnet are used for beam focusing, the diode magnet is used to change the beam direction to meet the layout requirements of the device, and the beam cutter is used to control the flow of the beam. Thus, after focusing, filtering, and transmission through the LEBT, the particle beam is transmitted to the beam track with parameters acceptable to injector 2, while impurities in the particle beam are removed.

[0022] Injector 2, located immediately after ion source system 1, is an accelerator used for preliminary beam acceleration. It pre-accelerates the particles generated by the ion source to ensure the beam meets the injection requirements of the synchrotron. At low energies, protons and helium ions are slow and exhibit strong space charge effects, making such beams unacceptable to synchrotron 4. Therefore, injector 2 is needed to boost the beam energy to a level suitable for synchrotron 4. Injector 2 incorporates a quadrupole magnet, a beam convergent, and a beam divergent to match beam parameters, ensuring effective acceleration of the beam within injector 2 and its appropriate parameters for entry into synchrotron 4 via injection system 3. Injector 2 is designed based on a particle charge-to-mass ratio of 1 / 2, enabling simultaneous acceleration of particles. and He 2+The outlet energy is above 8 MeV / u. As shown in Figure 1, the helium ion therapy device also includes a medical isotope preparation 10, which is optionally connected to the injection system 3. The outlet energy selection of the injector 2 can be applied to medical isotope production and achieve a high yield. Specifically, the injector 2 consists of a radio frequency quadruple field accelerator (RFQ), a drifting tube linear accelerator (DTL), and a medium-energy transmission line arranged sequentially. The RFQ is an acceleration structure invented to address the characteristics of proton beams at low energies. It mainly uses four electrodes to generate a strong focusing effect, solving the problem of increased emissivity of proton beams at low energies. At the same time, modulation is added to the electrode head to produce an acceleration effect. In this invention, the RFQ is four-wing type. The electrodes of the four-wing type RFQ are directly connected to the cavity wall. Positive and negative voltages are achieved through circumferential phase difference. The four electrodes generate a strong focusing effect, solving the problem of increased emissivity of proton beams at low energies. At the same time, modulation is added to the electrode head to produce an acceleration effect. The quad-wing RFQ can be applied to higher frequencies, and furthermore, high-frequency quad-wing RFQs have a smaller size. Specifically, quad-wing RFQs are used at frequencies above 200 MHz, with their tips forming a "wing-like" structure. Heat accumulated at the tip can be transferred to the wings and dissipated through the water-cooling pipes of the wings. The higher the frequency of the quad-wing RFQ, the smaller its size. The RFQ of the injector 2 of the helium ion therapy device A according to the present invention operates at a frequency of 425 MHz, which is higher than the frequency of existing heavy ion RFQs, thus resulting in a smaller size. This allows for a higher acceleration gradient through a compact design and a shorter injector section. The challenge lies in the fact that the focusing intensity of the RFQ is inversely proportional to the frequency; the higher the frequency, the lower the focusing intensity, and the greater the probability of beam loss during acceleration, i.e., a decrease in transmission efficiency. In this invention, the RFQ uses a special design method of variable focusing intensity and variable beam aperture, achieving high transmission efficiency even at higher frequencies. The DTL is an accelerator structure composed of a drift tube and an acceleration gap. When the proton velocity β is between 0.1 and 0.1, the DTL is the most suitable accelerator type. Traditional DTL types, such as the Alvarez-type DTL, have low acceleration gradients and long lengths for accelerating the same energy. Furthermore, this type of DTL requires the addition of a permanent magnet quadrupole within the drift tube, which is technically challenging, prone to errors, and difficult to adjust after fabrication. In this invention, the DTL is the IH-DTL designed by KONUS Beam Dynamics, which achieves a higher acceleration gradient, significantly reduces the DTL length, and eliminates the need for the magnet to be installed inside the drift tube, reducing manufacturing complexity. It also allows for a wider range of magnet selection, including electromagnetic quadrupoles, and enables adjustments to address errors during actual debugging and operation. The main challenge lies in its relatively weak focusing effect.Heavy ions have very low energy and a large space charge effect during the injector stage, making them more prone to divergence during acceleration. Therefore, the structural design of the IH-DTL needs more detailed optimization to achieve better beam quality and high transmission efficiency. The medium-energy transmission line mainly includes a quadrupole magnet and a beam gatherer, used to adjust the beam parameters from the upstream accelerator to meet the acceptance requirements of the downstream accelerator. In this invention, a beam stripper is provided on the medium-energy transmission line to... It is stripped into protons p.

[0023] The injection system 3 is designed 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; therefore, the beam cannot directly enter the synchrotron 4. The injection system 3 uses a combination of diode magnets to deflect the particle beam in a suitable direction, and employs devices such as beam kickers and cutters to achieve the beam trajectory transformation.

[0024] Synchrotron 4 is a circular accelerator that accelerates the beam to the required energy. The strength of the magnets in the accelerator increases with the particle beam energy to achieve synchronization. Synchrotron 4 uses a combination of dipole and quadrupole magnets, along with a control system, to achieve synchronous changes in magnetic field strength and gradient with increasing particle beam energy. Synchrotron 4 uses eight dipole magnets, forming an octagonal shape. The strength of the dipole magnets changes with the beam energy, controlled by the magnet power supply. In detail, the synchrotron involved in this invention is improved and different from existing medical synchrotrons. Synchrotron 4 is designed primarily based on helium ion specifications, with a circumference of less than 28 meters, achieving miniaturization of the accelerator. Simultaneously, it can accelerate protons by controlling the magnets. Synchrotron 4 can simultaneously accelerate p and He. 2+ It can accelerate protons (p) to 235 MeV and accelerate helium ions (He). 2+ Accelerated to 235 MeV / u. The proton energy can be accelerated to even higher levels, up to 750 MeV, which can meet the requirements of proton CT.

[0025] The extraction system 5 is designed to match the beam trajectory and extract the beam from synchrotron 4. Using a combination of dipole magnets and a cutting plate, extraction system 5 orderly extracts the particle beam in a manner consistent with resonance theory, guiding it onto its subsequent straight trajectory. Extraction system 5 can simultaneously utilize p and He energies. 2+ Extraction system 5 is a slow extraction system, with the slow extraction at the 2 / 3 resonance point being optimal, meeting the beam parameter requirements for helium ion therapy.

[0026] The beam transport system 6 is a device for transporting and matching the beam, transmitting it to the treatment chamber 7 and matching it to the required precision and dimensions for treatment, thus meeting the beam cross-sectional dimensions required for tumor treatment. In the proton-helium ion therapy device A, at least two treatment chambers 7 are provided. The beam parameters extracted from the synchrotron 4 do not meet the treatment requirements and cannot be used directly for treatment; instead, they are transmitted to the treatment chambers 7 via the beam transport system 6. The beam transport system 6 includes components for p and He ions. 2+ An optimized high-energy transmission line. Specifically, the beam transmission system 6 consists of a diode magnet, a quadrupole magnet, and a correction magnet, 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 beam parameters. After passing through the beam transmission system 6, the lateral dimension of the beam is less than 10 mm, meeting the needs of treatment.

[0027] The treatment chamber 7 includes either a fixed-beam treatment chamber 71 or a rotating-beam treatment chamber 72. In the fixed-beam treatment chamber 71, the beam direction remains constant, irradiating the affected area at a fixed angle. The beam transmission system 6 in the fixed-beam treatment chamber 71 ensures the beam reaches the affected area with the required precision. In the rotating-beam treatment chamber 72, the beam direction can be changed according to treatment needs, irradiating the affected area at multiple angles. The beam transmission system 6 includes a rotating gantry 61, a rotatable mechanical support structure located within the rotating-beam treatment chamber 72 to achieve angle changes, thus fulfilling treatment requirements. In the rotating-beam treatment chamber 72, the diode magnets on the rotating gantry 61 are superconducting diode magnets, with a field strength reaching 4T, allowing for a smaller size of the rotating gantry 61. The size of the rotating gantry 61 is primarily influenced by the bending radius of the diode magnets. Due to the high magnetic stiffness of heavy ions, superconducting diode magnets can achieve higher magnetic field strength, reducing the bending radius and enabling miniaturization of the rotating gantry.

[0028] Treatment room 7 includes a treatment system comprising a treatment head, treatment bed, positioning system, respiratory gating, and treatment control system, enabling final treatment within the treatment room and better meeting the diverse needs of cancer patients for particle beam therapy. The treatment head can deflect the beam to achieve scanning irradiation of the affected area. The treatment head is designed for use with He... 2+ The treatment head is used to immobilize the patient and, in conjunction with the treatment head, to deliver irradiation at different angles as planned. A positioning system is used to locate the patient and affected area, ensuring treatment precision. A respiratory gating system monitors the patient's respiratory movements and, in conjunction with the treatment head, adjusts the treatment depth in real time, reducing damage to healthy tissues and cells. The treatment control system serves as the medium for medical staff to operate the various treatment devices. Notably, treatment room 7 is equipped with a proton CT scanner, which, in conjunction with proton-helium ion therapy, provides even more precise positioning.

[0029] According to the proton-helium ion therapy device A of the present invention, the maximum energy required for helium ions used in treatment is 235 MeV / 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 an accelerator, gantry, and treatment head) is smaller and less expensive. Simultaneously, the helium ion device is also compatible with protons, providing a variety of particle types for treatment. Preferably, in 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 there is currently no precedent for the application of IH-DTL in heavy ion (referring to ions with a mass greater than that of protons) therapy devices; the magnet technology used in the synchrotron can effectively reduce the circumference of the synchrotron; the injection extraction system can better meet the extraction requirements of heavy ions at different energies through variable electrode spacing and cutting plate deflection angle; the beam transmission system can not only ensure the basic requirement of beam distribution to different treatment chambers, but also improve the stability of the system; in the rotating beam treatment chamber, because the beam transmission system uses superconducting magnets, the size of the rotating gantry is smaller than that of existing heavy ion therapy rotating gantry; a proton CT can also be equipped in the treatment chamber to improve the accuracy of positioning.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A proton-helium ion therapy device based on a synchrotron, characterized in that, The proton-helium ion therapy device includes an ion source system, an injector, an injection system, a synchrotron, an extraction system, a beam transmission system, and a treatment chamber. The ion source system generates ion energy through two electron cyclotron resonance ion sources. Helium ions, and injectors include quad-wing RFQ and IH-DTL. Alternatively, helium ions can be initially accelerated to 8 MeV / u using a quad-wing RFQ and IH-DTL. After being stripped into protons by a stripper, the protons or helium ions are injected into the synchrotron via an injection system. The synchrotron accelerates the protons or helium ions to 235 MeV / u and then extracts them from the synchrotron via an extraction system. The extracted protons or helium ions are then transported through a beam transmission system to make their lateral dimensions less than 10 mm before entering the treatment room for treatment.

2. The proton-helium ion therapy device according to claim 1, characterized in that, The quad-wing RFQ operates at a frequency of 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 installed to... It is stripped into protons.

5. The proton-helium ion therapy device according to claim 4, characterized in that, Synchrotrons accelerate protons to 235 MeV to 750 MeV.

6. The proton-helium ion therapy device according to claim 5, characterized in that, The treatment room is equipped with a proton CT scanner, which is used in conjunction with 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 consists of eight dipole magnets. Synchronization is achieved by controlling the power supply to the magnets so that the strength of the dipole magnets changes with the beam energy.

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 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.

10. The proton-helium ion therapy device according to claim 9, characterized in that, The beam delivery system includes a rotating gantry extending into the rotating beam therapy chamber, and the diode magnets on the rotating gantry are superconducting diode magnets.

Images