A synchrotron for a proton-helium ion therapy device

Abstract

The application relates to a synchrotron for a proton-helium ion therapy device, which comprises eight dipole deflection magnets connected in sequence through eight straight-line sections to form a ring structure, the deflection angle of the eight dipole deflection magnets is 45 degrees, and the maximum magnetic field strength is 2.4T; the eight straight-line sections comprise four long straight-line sections and four short straight-line sections, which are used for accelerating the helium ion beam from an injection energy of 8-10 MeV / u to 200-235 MeV / u and leading out for helium ion therapy, or accelerating the proton beam from an injection energy of 8-10 MeV to 200-750 MeV and leading out for proton therapy. According to the synchrotron for the proton-helium ion therapy device, the structure is very compact, unnecessary gaps and magnet elements are reduced, the circumference of the whole accelerator is reduced, the space of the synchrotron is effectively utilized, and the construction cost of the device and the building is reduced to the maximum extent, and the treatment cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a medical synchrotron for tumor treatment, and more particularly to a synchrotron for a proton-helium ion treatment device. BACKGROUND

[0002] Particle beam therapy is a radiation therapy technique that uses high-energy particle beams, such as protons, helium ions (He 2+ ) beams, to directly target tumor tissues, providing high-precision radiation doses for therapeutic purposes.

[0003] The principle of helium ion therapy is to take advantage of the specific energy deposition characteristics of helium ions in tissues. Compared with traditional X-ray radiotherapy, the helium ion beam can reach the maximum radiation dose at a specific depth inside the body, and quickly attenuate after passing through the tissue, reducing damage to surrounding normal tissues.

[0004] The development of this technology benefits from advances in accelerator technology, enabling particle beam radiation therapy to more accurately target tumors and provide more effective treatment. Currently, helium ion therapy is still in the stage of continuous development and improvement, but has shown potential advantages in the treatment of certain types of tumors.

[0005] Although the helium ion therapy technology has many advantages, it also faces some challenges. Currently, there is no helium ion treatment device in China, and the most advanced is the proton treatment device. At the same time, the magnetic steel degree of helium ions is twice that of protons, and if the magnet length of the proton treatment device is directly scaled to the length corresponding to the magnetic steel degree of helium ions according to the magnetic field strength, the envelope function is larger, the magnets are not compact enough, the overall circumference is larger, and the cost is higher. SUMMARY

[0006] In order to solve the problem of large overall circumference in the prior art, the present application provides a synchrotron for a proton-helium ion treatment device.

[0007] The synchrotron for proton helium ion therapy device according to the application comprises eight dipole deflection magnets connected in sequence by eight straight-line sections to form a ring structure, the deflection angle of the eight dipole deflection magnets is 45 degrees and the maximum magnetic field strength is 2.4T, the eight straight-line sections comprise four long straight-line sections and four short straight-line sections, wherein the first long straight-line section connects the eighth dipole deflection magnet and the first dipole deflection magnet, the second long straight-line section connects the first dipole deflection magnet and the second dipole deflection magnet, the third long straight-line section connects the fourth dipole deflection magnet and the fifth dipole deflection magnet, the fourth long straight-line section connects the fifth dipole deflection magnet and the sixth dipole deflection magnet, the first short straight-line section connects the second dipole deflection magnet and the third dipole deflection magnet, the second short straight-line section connects the third dipole deflection magnet and the fourth dipole deflection magnet, the third short straight-line section connects the sixth dipole deflection magnet and the seventh dipole deflection magnet, and the fourth short straight-line section connects the seventh dipole deflection magnet and the eighth dipole deflection magnet, which is used for accelerating the helium ion beam from the injection energy of 8-10 MeV / u to 200-235 MeV / u and extracting for helium ion therapy, or accelerating the proton beam from the injection energy of 8-10 MeV to 200-750 MeV and extracting for proton therapy.

[0008] Preferably, the edge angle of the eight dipole deflection magnets is 0-15 degrees and the magnetic field strength is 0.21-2.4T.

[0009] Preferably, the length of the eight dipole deflection magnets is 1.53 meters respectively.

[0010] Preferably, the first long straight-line section comprises a first horizontal defocusing quadrupole magnet close to the first dipole deflection magnet and a first horizontal focusing quadrupole magnet close to the eighth dipole deflection magnet, the second long straight-line section comprises a second horizontal focusing quadrupole magnet close to the first dipole deflection magnet and a second horizontal defocusing quadrupole magnet close to the second dipole deflection magnet, the first short straight-line section comprises a second sextupole magnet close to the second dipole deflection magnet and a third horizontal focusing quadrupole magnet close to the third dipole deflection magnet, the second short straight-line section comprises a third horizontal defocusing quadrupole magnet, the third long straight-line section comprises a fourth horizontal focusing quadrupole magnet close to the fourth dipole deflection magnet and a fourth horizontal defocusing quadrupole magnet close to the fifth dipole deflection magnet, the fourth long straight-line section comprises a fifth horizontal focusing quadrupole magnet close to the fifth dipole deflection magnet and a fifth horizontal defocusing quadrupole magnet close to the sixth dipole deflection magnet, the third short straight-line section comprises a fourth sextupole magnet close to the sixth dipole deflection magnet and a sixth horizontal focusing quadrupole magnet close to the seventh dipole deflection magnet, and the fourth short straight-line section comprises a sixth horizontal defocusing quadrupole magnet.

[0011] Preferably, the first long straight section is a 1.83-meter long first extraction straight section, the second long straight section is a 2-meter long second extraction straight section, the third long straight section is a 1.83-meter long injection straight section, and the fourth long straight section is a 2-meter long high frequency system.

[0012] Preferably, the six horizontal focusing quadrupole magnets each have a length of 0.2 meters, and the six horizontal defocusing quadrupole magnets each have a length of 0.3 meters.

[0013] Preferably, the maximum gradient of the twelve quadrupole magnets can reach 9.25 T / m.

[0014] Preferably, the integral magnetic field of the six horizontal focusing quadrupole magnets ranges from 0.16 T to 1.85 T, and the integral magnetic field of the six horizontal defocusing quadrupole magnets ranges from -0.23 T to -2.66 T.

[0015] Preferably, the first long straight section further comprises a first sextupole magnet close to the first horizontal focusing quadrupole magnet, and the third long straight section further comprises a third sextupole magnet close to the fourth horizontal focusing quadrupole magnet.

[0016] Preferably, the first long straight section further comprises a first extraction element between the first horizontal defocusing quadrupole magnet and the first sextupole magnet, the second long straight section further comprises a second extraction element between the second horizontal defocusing quadrupole magnet and the second horizontal focusing quadrupole magnet, and the third long straight section further comprises an injection element between the fourth horizontal defocusing quadrupole magnet and the third sextupole magnet.

[0017] The synchrotron for a proton-helium ion therapy device according to the present application has a very compact structure, reduces unnecessary gaps and magnet elements, reduces the circumference of the entire accelerator, effectively utilizes the space of the synchrotron, and further maximally reduces the construction cost of the device and the building, thereby reducing the treatment cost. In summary, the synchrotron for a proton-helium ion therapy device according to the present application can reduce the envelope function, further reduce the total circumference, and reduce the construction cost of the therapy device. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A full-ring layout of a synchrotron for a proton-helium ion therapy device according to one preferred embodiment of the present application is shown.

[0019] Figure 2 A beam envelope function of the synchrotron of Figure 1 is shown.

[0020] Figure 3 is a structural schematic diagram of a 1J22 dipole deflection magnet with a thickness of 0.00 mm.

[0021] Figure 4is a structural schematic diagram of a dipole deflection magnet of 1J22 with a thickness of 2.00 mm.

[0022] Figure 5 is a structural schematic diagram of a dipole deflection magnet of 1J22 with a thickness of 10.00 mm. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present application will be described below in detail with reference to the accompanying drawings.

[0024] As Figure 1 shown, the synchrotron for proton-helium ion therapy device according to one preferred embodiment of the present application comprises eight dipole deflection magnets 1-8 connected in sequence by eight straight sections 10-80 to form a ring structure, with the beam direction being Figure 1 the clockwise direction of the ring structure, for accelerating the helium ion beam from the injection energy of 8-10 MeV / u to 200-235 MeV / u and extracting it for helium ion therapy, or accelerating the proton beam from the injection energy of 8-10 MeV to 200-750 MeV and extracting it for proton therapy, solving the problem of the lack of helium ion synchrotron therapy device and the large floor area of the particle beam accelerator therapy device.

[0025] The eight straight sections 10-80 comprise four long straight sections 10-40 and four short straight sections 50-80, wherein the first long straight section 10 connects the eighth dipole deflection magnet 8 and the first dipole deflection magnet 1, the second long straight section 20 connects the first dipole deflection magnet 1 and the second dipole deflection magnet 2, the third long straight section 30 connects the fourth dipole deflection magnet 4 and the fifth dipole deflection magnet 5, the fourth long straight section 40 connects the fifth dipole deflection magnet 5 and the sixth dipole deflection magnet 6, the first short straight section 50 connects the second dipole deflection magnet 2 and the third dipole deflection magnet 3, the second short straight section 60 connects the third dipole deflection magnet 3 and the fourth dipole deflection magnet 4, the third short straight section 70 connects the sixth dipole deflection magnet 6 and the seventh dipole deflection magnet 7, and the fourth short straight section 80 connects the seventh dipole deflection magnet 7 and the eighth dipole deflection magnet 8.

[0026] The first long straight section 10 comprises a first horizontal defocusing quadrupole magnet 11 close to the first dipole deflection magnet 1 and a first horizontal focusing quadrupole magnet 21 close to the eighth dipole deflection magnet 8. In addition, the first long straight section 10 further comprises a first sextupole magnet 31 close to the first horizontal focusing quadrupole magnet 21. Furthermore, the first long straight section 10 further comprises a first extraction element 41 located between the first horizontal defocusing quadrupole magnet 11 and the first sextupole magnet 31.

[0027] The second long straight line section 20 comprises a second horizontal focusing quadrupole magnet 22 near the first deflection dipole magnet 1 and a second horizontal defocusing quadrupole magnet 12 near the second deflection dipole magnet 2. In addition, the second long straight line section 20 further comprises a second extraction element 42 between the second horizontal defocusing quadrupole magnet 12 and the second horizontal focusing quadrupole magnet 22.

[0028] The first short straight line section 50 comprises a second sextupole magnet 32 near the second deflection dipole magnet 2 and a third horizontal focusing quadrupole magnet 23 near the third deflection dipole magnet 3.

[0029] The second short straight line section 60 comprises a third horizontal defocusing quadrupole magnet 13.

[0030] The third long straight line section 30 comprises a fourth horizontal focusing quadrupole magnet 24 near the fourth deflection dipole magnet 4 and a fourth horizontal defocusing quadrupole magnet 14 near the fifth deflection dipole magnet 5. In addition, the third long straight line section 30 further comprises a third sextupole magnet 33 near the fourth horizontal focusing quadrupole magnet 24. Furthermore, the third long straight line section 30 further comprises an injection element 51 between the fourth horizontal defocusing quadrupole magnet 14 and the third sextupole magnet 33.

[0031] The fourth long straight line section 40 comprises a fifth horizontal focusing quadrupole magnet 25 near the fifth deflection dipole magnet 5 and a fifth horizontal defocusing quadrupole magnet 15 near the sixth deflection dipole magnet 6.

[0032] The third short straight line section 70 comprises a fourth sextupole magnet 34 near the sixth deflection dipole magnet 6 and a sixth horizontal focusing quadrupole magnet 26 near the seventh deflection dipole magnet 7.

[0033] The fourth short straight line section 80 comprises a sixth horizontal defocusing quadrupole magnet 16.

[0034] The above-mentioned components are connected by the vacuum chamber of the device (indicated by the straight lines between the elements in the figure) to form the optical structure (i.e. the magnetic focusing structure) of the accelerator, which has two superperiods (i.e. two identical parts, see Figure 2 , the longitudinal coordinate beta function and the longitudinal coordinate dispersion function at the positions 14-28 meters on the horizontal coordinate are exactly the same as the longitudinal coordinate values at the positions 0-14 meters), each superperiod having straight line sections (two short straight line sections and two long straight line sections) and arc line sections (four deflection dipole magnets).

[0035] Figure 2 The horizontal and vertical beam envelope functions of the present application, wherein the longitudinal coordinate represents the size of the function in meters (m) and the horizontal coordinate represents the longitudinal position in the synchrotron in meters (m). The functions are derived from Figure 2It can be seen that the application has the characteristics of small envelope function and large effective acceptance, and simulation calculation shows that more protons or helium ions can be stored.

[0036] It should be understood that the difficulty of the application lies in compact structure. If the energy of the proton synchrotron is 750 MeV according to the current technology (protons of 750 MeV have the same magnetic steel degree as helium ions of 235 MeV / u, and the same technical requirements for the magnet), a circumference of about 47 meters is required, while the application uses super-high field dipole magnets and shorter long straight section design to shorten the circumference of the helium ion synchrotron to 28 meters.

[0037] The edge angle of each of the eight dipole deflection magnets 1-8 is 0-15°, and the magnetic field strength is 0.21-2.4T. In this embodiment, the length of each of the eight dipole deflection magnets 1-8 is 1.53 meters, the deflection angle is 45 degrees, and the edge angle is 0 degrees. Compared with the dipole deflection magnet in the prior art with a magnetic field strength of 1.7 Tesla (T), the maximum magnetic field strength of the eight dipole deflection magnets 1-8 of the application is 2.4 Tesla. Referring to Figures 3-5 , the eight dipole deflection magnets 1-8 of the application use iron-cobalt alloy sheet material with a thickness in the range of 0-10.0mm to replace the traditional silicon steel material, such as 1J22, with a magnetic permeability (μ)≥2.30T, which can increase the maximum magnetic field strength B of the dipole deflection magnet 1-8 from 2.2T to 2.4T, overcome the saturation constraint of the ordinary silicon steel pole head magnetic field, and enhance the magnetic field of the dipole magnet, thereby reducing the circumference of the entire synchrotron.

[0038] The integral magnetic field range of the six horizontal focusing quadrupole magnets is 0.16-1.85T, and the integral magnetic field range of the six horizontal defocusing quadrupole magnets is -0.23T to -2.66T. In this embodiment, the length of each of the six horizontal focusing quadrupole magnets 21-26 is 0.2 meters, and the length of each of the six horizontal defocusing quadrupole magnets 11-16 is 0.3 meters. In particular, by increasing the magnetic field of the dipole deflection magnet and the compact spatial layout, the beam envelope function is effectively reduced, and under the same magnet aperture, the gradient of the quadrupole magnet can be further increased, and the maximum gradient of the quadrupole magnet can reach 9.25 Tesla per meter (T / m).

[0039] In the embodiment, the first long straight section 10 is a first extraction straight section with a length of 1.83 meters, the second long straight section 20 is a second extraction straight section with a length of 2 meters, the third long straight section 30 is an injection straight section with a length of 1.83 meters, and the fourth long straight section 40 is a high frequency system (i.e. a radio frequency acceleration system) with a length of 2 meters. According to the comparison of the magnetic steel degree under the proton energy of 250 MeV and the helium ion energy of 235 MeV / u, the length of the long straight section of the conventional helium ion is about 3.8 meters. In sharp contrast, the present application realizes the injection of the helium ion (or proton) beam with the highest energy of 10 MeV / u in the 1.83-meter long straight section, and realizes the extraction of the helium ion (or proton) beam with the highest energy of 235 MeV / u in the 2-meter and 1.83-meter long straight sections.

[0040] In summary, the ion in the synchrotron for the proton helium ion treatment device of the present application can be either a proton or a helium ion (both ions are not in the accelerator at the same time). The energy of the helium ion beam during injection is 8-10 MeV / u, and finally needs to be accelerated to the highest energy of 235 MeV / u, or the proton beam with the injection energy of 8-10 MeV is accelerated to the highest energy of 750 MeV. The present application adopts eight deflection dipole magnets with a magnetic field strength of 2.4 Tesla to reduce the envelope function and shorten the circumference, and six horizontal focusing quadrupole magnets and six horizontal defocusing quadrupole magnets can effectively control the size of the envelope function. The present application effectively increases the acceptance of the synchrotron by controlling the envelope function in a smaller horizontal direction through the design of shorter long straight sections, increases the number of stored helium ions (or protons), shortens the treatment time, and the structure of the entire accelerator is very compact, the circumference is small, and the occupied area is small.

[0041] The above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application. The above embodiment of the present application can be variously changed. Any simple, equivalent changes and modifications made according to the content of the claims and the description of the present application fall within the scope of protection of the present application. The present application is not described in detail.

Claims

1. A synchrotron for a proton-helium ion therapy device, characterized in that, The synchrotron comprises eight dipolar deflecting magnets connected sequentially by eight linear joints to form a ring structure. Each of the eight deflecting magnets has a deflection angle of 45 degrees and a maximum magnetic field strength of 2.4 T. The eight linear joints include four long linear joints and four short linear joints. The first long linear joint connects the eighth deflecting magnet to the first deflecting magnet; the second long linear joint connects the first deflecting magnet to the second deflecting magnet; and the third long linear joint connects the fourth deflecting magnet to the... Five deflecting diodes are used. A fourth long straight joint connects the fifth and sixth deflecting diodes; a first short straight joint connects the second and third deflecting diodes; a second short straight joint connects the third and fourth deflecting diodes; a third short straight joint connects the sixth and seventh deflecting diodes; and a fourth short straight joint connects the seventh and eighth deflecting diodes. This system is used to accelerate a helium ion beam from an injection energy of 8-10 MeV / u to 200-235 MeV / u and extract it for helium ion therapy, or to accelerate a proton beam from an injection energy of 8-10 MeV to 200-750 MeV / u. MeV was introduced for proton therapy. The eight dipolar deflecting magnets all have edge angles of 0–15° and magnetic field strengths of 0.21–2.4 T. The lengths of the eight dipolar deflecting magnets are 1.53 meters each. The first long straight section includes the first horizontally defocused quadrupole magnet near the first deflecting dipolar magnet and the first horizontally focusing quadrupole magnet near the eighth deflecting dipolar magnet. The second long straight section includes the second horizontally focusing quadrupole magnet near the first deflecting dipolar magnet and the second horizontally defocused quadrupole magnet near the second deflecting dipolar magnet. The first short straight section includes the second hexapole magnet near the second deflecting dipolar magnet and the third horizontally focusing quadrupole magnet near the third deflecting dipolar magnet. The second short straight section includes the third horizontally defocused quadrupole magnet. The third long straight section… The section includes a fourth horizontally focusing quadrupole magnet near the fourth deflecting diode magnet and a fourth horizontally defocusing quadrupole magnet near the fifth deflecting diode magnet; the fourth long straight section includes a fifth horizontally focusing quadrupole magnet near the fifth deflecting diode magnet and a fifth horizontally defocusing quadrupole magnet near the sixth deflecting diode magnet; the third short straight section includes a fourth hexapole magnet near the sixth deflecting diode magnet and a sixth horizontally focusing quadrupole magnet near the seventh deflecting diode magnet; the fourth short straight section includes a sixth horizontally defocusing quadrupole magnet; the first long straight section is a 1.83-meter-long first lead-out straight section; the second long straight section is a 2-meter-long second lead-out straight section; the third long straight section is a 1.83-meter-long injection straight section; and the fourth long straight section is a 2-meter-long high-frequency system.

2. The synchrotron according to claim 1, characterized in that, The lengths of the six horizontally focusing quadrupole magnets are 0.2 meters each, and the lengths of the six horizontally defocusing quadrupole magnets are 0.3 meters each.

3. The synchrotron according to claim 1, characterized in that, The maximum gradient of the twelve quadrupole magnets can reach 9.25 T / m.

4. The synchrotron according to claim 1, characterized in that, The integrated magnetic field range of the six horizontally focused quadrupole magnets is 0.16~1.85T, and the integrated magnetic field range of the six horizontally defocused quadrupole magnets is -0.23T~-2.66T.

5. The synchrotron according to claim 1, characterized in that, The first long straight section also includes a first hexagonal magnet near the first horizontally focused quadrupole magnet, and the third long straight section also includes a third hexagonal magnet near the fourth horizontally focused quadrupole magnet.

6. The synchrotron according to claim 1, characterized in that, The first long straight section also includes a first lead-out element located between the first horizontally defocused quadrupole magnet and the first hexapole magnet; the second long straight section also includes a second lead-out element located between the second horizontally defocused quadrupole magnet and the second horizontally focused quadrupole magnet; and the third long straight section also includes an injection element located between the fourth horizontally defocused quadrupole magnet and the third hexapole magnet.

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