Medical proton synchrotron

Abstract

The present invention relates to a medical proton synchrotron, which comprises eight deflection dipole magnets connected in sequence, four long straight sections connected between two deflection dipole magnets, respectively, and four mini straight sections connected between two deflection dipole magnets, respectively, and the straight sections comprise six horizontal defocusing quadrupole magnets and six horizontal focusing quadrupole magnets. According to the medical proton synchrotron of the present invention, the envelope function is controlled in a smaller level, thereby effectively increasing the acceptance of the synchrotron, maintaining a very compact structure, reducing the manufacturing difficulty of the elements, and improving the extraction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to tumor treatment, more particularly to a medical proton synchrotron. BACKGROUND

[0002] The excellent Bragg peak characteristics of protons in the depth direction make it one of the most advanced means of tumor treatment, and there are more and more proton treatment devices and treatment centers being built in the world. The proton cancer treatment accelerators currently in operation and under construction are mainly cyclotrons and synchrotrons.

[0003] The cyclotron can provide stable continuous beams, and the beam cutting and opening speed is fast, which can meet the requirements of respiratory gating. However, the cyclotron relies on a mechanical device installed on the high-energy line, i.e., an energy reducer, to reduce the beam energy by scattering; the advantage is that the energy adjustment is rapid, and the energy can be changed at a speed of 50 milliseconds per step, which can support a fast repetitive scanning mode to treat moving tumors; but the disadvantage is that the scattering causes a very low beam utilization rate, and the through efficiency is less than 1% when the minimum energy is 70 MeV during treatment; the scattering caused by the energy reduction and the subsequent energy selection cause a large amount of beam loss, which will result in a lot of radiation, and the radiation protection and equipment safety will be under great pressure.

[0004] Compared with the cyclotron, the obvious advantage of the synchrotron is that it can conveniently adjust the energy of the beam to adapt to the need for accurate changes in ion energy for radiation therapy, and does not need an additional energy reducer, which can ensure a relatively clean (low radiation) environment. After adopting a new multi-energy extraction method, the inherent slow energy conversion time, long ineffective treatment time and inability to adapt to fast repetitive scanning are basically eliminated.

[0005] There is a patent document CN105392270A that designs a proton synchrotron composed of 8 deflection dipole magnets, but the accelerator has the disadvantages of large envelope function, etc. SUMMARY

[0006] In order to solve the above-mentioned problems of large envelope function in the prior art, the present application provides a medical proton synchrotron.

[0007] The medical proton synchrotron according to the application comprises first to eighth deflection dipole magnets connected in sequence, the eighth deflection dipole magnet being connected with the first deflection dipole magnet to form a ring structure; first to fourth long straight line sections connected between the first and eighth deflection dipole magnets, the first and second deflection dipole magnets, the fourth and fifth deflection dipole magnets and the fifth and sixth deflection dipole magnets respectively; and first to fourth mini straight line sections connected between the second and third deflection dipole magnets, the third and fourth deflection dipole magnets, the sixth and seventh deflection dipole magnets and the seventh and eighth deflection dipole magnets respectively; wherein the first long straight line section comprises a first horizontal focusing quadrupole magnet arranged close to the first deflection dipole magnet and a first horizontal focusing quadrupole magnet arranged close to the eighth deflection dipole magnet; the second long straight line section comprises a second horizontal focusing quadrupole magnet arranged close to the first deflection dipole magnet and a second horizontal focusing quadrupole magnet arranged close to the second deflection dipole magnet; the first mini straight line section comprises a third horizontal focusing quadrupole magnet; the second mini straight line section comprises a third horizontal focusing quadrupole magnet; the third long straight line section comprises a fourth horizontal focusing quadrupole magnet arranged close to the fourth deflection dipole magnet and a fourth horizontal focusing quadrupole magnet arranged close to the fifth deflection dipole magnet; the fourth long straight line section comprises a fifth horizontal focusing quadrupole magnet arranged close to the fifth deflection dipole magnet and a fifth horizontal focusing quadrupole magnet arranged close to the sixth deflection dipole magnet; the third mini straight line section comprises a sixth horizontal focusing quadrupole magnet; and the fourth mini straight line section comprises a sixth horizontal focusing quadrupole magnet.

[0008] Preferably, the first long straight-line section further comprises an injection electrostatic cutting plate connected between the first horizontal defocusing quadrupole magnet and the first horizontal focusing quadrupole magnet, an injection electrostatic cutting magnet connected with the injection electrostatic cutting plate, and a first resonant sextupole magnet and a transverse high-frequency exciting electrode connected between the injection electrostatic cutting plate and the first horizontal focusing quadrupole magnet in sequence; the second long straight-line section further comprises a first injection convex-rail magnet connected between the second horizontal defocusing quadrupole magnet and the second horizontal focusing quadrupole magnet in sequence, and a high-frequency accelerating device connected between the first deflection dipole magnet and the second horizontal focusing quadrupole magnet; the third long straight-line section further comprises a second resonant sextupole magnet connected between the fourth horizontal focusing quadrupole magnet and the fourth horizontal defocusing quadrupole magnet, and an extraction electrostatic cutting plate connected between the second resonant sextupole magnet and the fourth horizontal defocusing quadrupole magnet; the fourth long straight-line section further comprises a first extraction electrostatic cutting magnet connected between the fifth deflection dipole magnet and the fifth horizontal focusing quadrupole magnet; and the fourth mini straight-line section further comprises a second injection convex-rail magnet connected between the sixth horizontal defocusing quadrupole magnet and the seventh deflection dipole magnet.

[0009] Preferably, the second long straight-line section further comprises a first fast quadrupole magnet connected between the first injection convex-rail magnet and the second horizontal focusing quadrupole magnet and arranged close to the first injection convex-rail magnet; and the fourth long straight-line section further comprises a second fast quadrupole magnet connected between the fifth horizontal focusing quadrupole magnet and the fifth horizontal defocusing quadrupole magnet.

[0010] Preferably, the first mini straight-line section further comprises a first horizontal focusing sextupole magnet connected between the third horizontal focusing quadrupole magnet and the third deflection dipole magnet; and the third mini straight-line section further comprises a second horizontal focusing sextupole magnet connected between the sixth horizontal focusing quadrupole magnet and the seventh deflection dipole magnet.

[0011] Preferably, the proton beam flow channel of the first extraction electrostatic cutting magnet passes through the interior of the fifth horizontal focusing quadrupole magnet.

[0012] The medical proton synchrotron according to the present application controls the envelope function at a smaller level, thereby effectively increasing the acceptance of the synchrotron, maintaining a very compact structure, reducing the manufacturing difficulty of the elements, and improving the extraction efficiency. The present application adjusts the position of the horizontal focusing quadrupole magnet, optimizes the angle of the extraction beam, and makes the extraction beam pass through the horizontal focusing quadrupole magnet with a special shape, thereby reducing the required strength of the electrostatic cutting magnet. In addition, the envelope function is controlled at a smaller level by using the reasonably distributed horizontal focusing and horizontal defocusing quadrupole magnets, thereby effectively increasing the acceptance of the synchrotron, increasing the number of stored protons, improving the utilization rate and duty cycle of protons, and shortening the treatment time. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a structural schematic diagram of a medical proton synchrotron according to a preferred embodiment of the present application.

[0014] Figure 2 is a schematic diagram of the envelope function of the medical proton synchrotron of Figure 1

[0015] Figure 3 is a schematic diagram of the extraction and storage beam trajectories of the medical proton synchrotron of Figure 1

[0016] Figure 4 is a schematic diagram of the extraction channel cross section of the medical proton synchrotron of Figure 1 at the fifth focusing quadrupole magnet. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present application will be described below in detail with reference to the accompanying drawings.

[0018] As shown in Figure 1 , the medical proton synchrotron according to a preferred embodiment of the present application comprises first to eighth deflection dipole magnets 1-8 connected in sequence, and the eighth deflection dipole magnet 8 is connected with the first deflection dipole magnet 1 to form a ring structure for deflecting the beam (the beam direction is counterclockwise in the ring structure). Figure 1

[0019] The medical proton synchrotron further comprises first to fourth long straight line sections connected between the first deflection dipole magnet 1 and the eighth deflection dipole magnet 8, the first deflection dipole magnet 1 and the second deflection dipole magnet 2, the fourth deflection dipole magnet 4 and the fifth deflection dipole magnet 5, and the fifth deflection dipole magnet 5 and the sixth deflection dipole magnet 6, respectively.

[0020] The medical proton synchrotron further comprises first to fourth mini straight line sections connected between the second deflection dipole magnet 2 and the third deflection dipole magnet 3, the third deflection dipole magnet 3 and the fourth deflection dipole magnet 4, the sixth deflection dipole magnet 6 and the seventh deflection dipole magnet 7, and the seventh deflection dipole magnet 7 and the eighth deflection dipole magnet 8, respectively.

[0021] The above components are connected through the vacuum chamber of the device (indicated by the straight lines connecting the elements in the figure).

[0022] ​​​Specifically, the first long straight-line section comprises: a first horizontal defocusing quadrupole magnet 11 arranged close to the first deflection dipole magnet 1, a first horizontal focusing quadrupole magnet 21 arranged close to the eighth deflection dipole magnet 8, an injection electrostatic cutting plate 54 connected between the first horizontal defocusing quadrupole magnet 11 and the first horizontal focusing quadrupole magnet 21, an injection electrostatic cutting magnet 53 connected with the injection electrostatic cutting plate 54, and a first resonant sextupole magnet 34 and a transverse high-frequency exciting electrode 63 connected between the injection electrostatic cutting plate 54 and the first horizontal focusing quadrupole magnet 21 in sequence.

[0023] Specifically, the second long straight-line section comprises: a high-frequency accelerating device 71 arranged close to the first deflection dipole magnet 1, a second horizontal defocusing quadrupole magnet 12 arranged close to the second deflection dipole magnet 2, a second horizontal focusing quadrupole magnet 22 arranged close to the high-frequency accelerating device 71, a first injection convex rail magnet 51 connected between the second horizontal defocusing quadrupole magnet 12 and the second horizontal focusing quadrupole magnet 22, and a first fast quadrupole magnet 41 connected between the first injection convex rail magnet 51 and the second horizontal focusing quadrupole magnet 22 and arranged close to the first injection convex rail magnet 51.

[0024] Specifically, the third long straight-line section comprises: a fourth horizontal focusing quadrupole magnet 24 arranged close to the fourth deflection dipole magnet 4, a fourth horizontal defocusing quadrupole magnet 14 arranged close to the fifth deflection dipole magnet 5, a second resonant sextupole magnet 32 connected between the fourth horizontal focusing quadrupole magnet 24 and the fourth horizontal defocusing quadrupole magnet 14, and an extraction electrostatic cutting plate 61 connected between the second resonant sextupole magnet 32 and the fourth horizontal defocusing quadrupole magnet 14.

[0025] Specifically, the fourth long straight-line section comprises: a first extraction electrostatic cutting magnet 62 arranged close to the fifth deflection dipole magnet 5, a fifth horizontal focusing quadrupole magnet 25 arranged close to the first extraction electrostatic cutting magnet 62, a fifth horizontal defocusing quadrupole magnet 15 arranged close to the sixth deflection dipole magnet 6, and a second fast quadrupole magnet 42 connected with the fifth horizontal focusing quadrupole magnet 25. In particular, a proton beam flow channel 81 of the first extraction electrostatic cutting magnet 62 passes through the inside of the fifth horizontal focusing quadrupole magnet 25.

[0026] Specifically, the first mini straight-line section comprises: a third horizontal focusing quadrupole magnet 23, and a first horizontal focusing sextupole magnet 31 connected between the third deflection dipole magnet 3 and the third horizontal focusing quadrupole magnet 23.

[0027] Specifically, the second mini straight-line section comprises: a third horizontal defocusing quadrupole magnet 13.

[0028] Specifically, the third mini linear section comprises a sixth horizontal focusing quadrupole magnet 26 and a second horizontal focusing sextupole magnet 33 connected between the sixth horizontal focusing quadrupole magnet 26 and the seventh deflection dipole magnet 7.

[0029] Specifically, the fourth mini linear section comprises a sixth horizontal defocusing quadrupole magnet 16 and a second injection convex rail magnet 52 connected between the sixth horizontal defocusing quadrupole magnet 16 and the seventh deflection dipole magnet 7.

[0030] In use, the medical proton synchrotron of the present application is used in a treatment cycle, in which low-energy proton beams provided by an injector are injected into the medical proton synchrotron through the injection static magnetic cutting magnet 53, the injection electrostatic cutting plate 54, the first and second injection convex rail magnets 51 and 52, the first to eighth deflection dipole magnets 1-8, and the like, and form a storage; then, according to the treatment requirements, the field strength of the synchronous rising deflection dipole magnets 1-8, the focusing quadrupole magnets 21-26 and the defocusing quadrupole magnets 11-16 is adjusted, and the energy of the protons is increased under the action of the high-frequency accelerating device 71. At the corresponding treatment energy, the protons are diffused to the extraction channel under the action of the RFKO excitation electrode 63, the first and second resonance sextupole magnets 32 and 34, and are extracted to the outside of the proton synchrotron through the extraction electrostatic cutting plate 61 and the first extraction electrostatic cutting magnet 62, and then to the patient. If necessary, the extraction can be stopped in this treatment cycle, and the energy can be switched to implement the extraction.

[0031] Figure 2 The horizontal and vertical beam envelope functions of the present application are shown in the following table, in which the longitudinal coordinate represents the size of the function, and the unit is meter (m), and the transverse coordinate represents the longitudinal position in the synchrotron, and the unit is meter (m). Figure 2 It can be seen that the present application has the characteristics of small envelope function and large effective acceptance, and simulation calculation shows that more protons can be stored.

[0032] The patent document CN105392270A actually has the disadvantages of low extraction efficiency, high strength of the extraction static cutting magnet, high energy consumption and the like. According to the medical proton synchrotron of the present application, on the basis of CN105392270A, the distance between the fifth horizontal focusing quadrupole magnet 25 and the adjacent fifth deflection dipole magnet 5 is increased to install the first extraction static cutting magnet 62, the distance between the second horizontal focusing quadrupole magnet 22 and the adjacent first deflection dipole magnet 1 is increased symmetrically, the distances of other magnets and the positions of part of the magnets are adjusted, the horizontal envelope at the first extraction electrostatic cutting plate is increased, and the envelope function at the first extraction electrostatic cutting magnet is reduced, the strength of the first resonance sextupole magnet and the second resonance sextupole magnet can be reduced, and the like. Figure 3The distance between the storage beam and the extraction beam at the first extraction electrostatic cutting magnet is increased, so as to reduce the strength of the first extraction electrostatic cutting magnet and improve the extraction efficiency. In order to keep the compact structure and good envelope function, the distance between the fifth horizontal focusing quadrupole magnet 25 and the adjacent fifth deflection dipole magnet 5 cannot be too long, so that the extraction beam is close to the storage beam. In order to make the extraction beam pass through the fifth horizontal focusing quadrupole magnet 25, the magnet yoke at the extraction beam is specially designed as shown. Figure 4 In addition, a pair of fast quadrupole magnets 41 and 42 are added to realize better control of the working point during extraction and better support for the multi-energy extraction function.

[0033] In summary, the application adopts eight deflection dipole magnets 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. In addition, the application can also use the above-mentioned quadrupole magnets and correction coils (not shown in the figure) in combination, thereby reducing the space occupation.

[0034] The above-mentioned is only the preferred embodiment of the application, and is not used to limit the scope of the application. The above-mentioned embodiments of the application can also be variously changed. That is, any simple, equivalent changes and modifications made according to the content of the claims and the description of the application fall within the scope of protection of the patent. The application is not described in detail, which is the conventional technical content.

Claims

1. A medical proton synchrotron characterized by comprising: The medical proton synchrotron comprises: sequentially connected first to eighth deflection dipole magnets (1-8), the eighth deflection dipole magnet (8) is connected with the first deflection dipole magnet (1) to constitute a ring structure; first to fourth long straight line sections connected between the first deflection dipole magnet (1) and the eighth deflection dipole magnet (8), the first deflection dipole magnet (1) and the second deflection dipole magnet (2), the fourth deflection dipole magnet (4) and the fifth deflection dipole magnet (5), and the fifth deflection dipole magnet (5) and the sixth deflection dipole magnet (6) respectively; and first to fourth mini straight line sections connected between the second deflection dipole magnet (2) and the third deflection dipole magnet (3), the third deflection dipole magnet (3) and the fourth deflection dipole magnet (4), the sixth deflection dipole magnet (6) and the seventh deflection dipole magnet (7), and the seventh deflection dipole magnet (7) and the eighth deflection dipole magnet (8) respectively; Wherein, the first long straight line section comprises a first horizontal defocusing quadrupole magnet (11) arranged close to the first deflection dipole magnet (1), a first horizontal focusing quadrupole magnet (21) arranged close to the eighth deflection dipole magnet (8), an injection electrostatic cutting plate (54) connected between the first horizontal defocusing quadrupole magnet (11) and the first horizontal focusing quadrupole magnet (21), an injection static magnetic cutting magnet (53) connected with the injection electrostatic cutting plate (54), and a first resonance sextupole magnet (34) and a transverse high frequency excitation electrode (63) connected between the injection electrostatic cutting plate (54) and the first horizontal focusing quadrupole magnet (21) in sequence; The second long straight line section comprises a second horizontal focusing quadrupole magnet (22) arranged close to the first deflection dipole magnet (1), a second horizontal defocusing quadrupole magnet (12) arranged close to the second deflection dipole magnet (2), a first injection convex rail magnet (51) connected between the second horizontal defocusing quadrupole magnet (12) and the second horizontal focusing quadrupole magnet (22), a first fast quadrupole magnet (41) connected between the first injection convex rail magnet (51) and the second horizontal focusing quadrupole magnet (22) and arranged close to the first injection convex rail magnet (51), and a high frequency accelerating device (71) connected between the first deflection dipole magnet (1) and the second horizontal focusing quadrupole magnet (22); The first mini straight line section comprises a third horizontal focusing quadrupole magnet (23); The second mini straight line section comprises a third horizontal defocusing quadrupole magnet (13); The third long straight line section comprises a fourth horizontal focusing quadrupole magnet (24) arranged close to the fourth deflection dipole magnet (4), a fourth horizontal defocusing quadrupole magnet (14) arranged close to the fifth deflection dipole magnet (5), a second resonance sextupole magnet (32) connected between the fourth horizontal focusing quadrupole magnet (24) and the fourth horizontal defocusing quadrupole magnet (14), and an extraction electrostatic cutting plate (61) connected between the second resonance sextupole magnet (32) and the fourth horizontal defocusing quadrupole magnet (14); The fourth long straight line section comprises a fifth horizontal focusing quadrupole magnet (25) arranged close to the fifth deflection dipole magnet (5), a fifth horizontal defocusing quadrupole magnet (15) arranged close to the sixth deflection dipole magnet (6), a first extraction static magnetic cut magnet (62) connected between the fifth deflection dipole magnet (5) and the fifth horizontal focusing quadrupole magnet (25), and a second fast quadrupole magnet (42) connected between the fifth horizontal focusing quadrupole magnet (25) and the fifth horizontal defocusing quadrupole magnet (15), and the proton beam channel (81) of the first extraction static magnetic cut magnet (62) passes through the inside of the fifth horizontal focusing quadrupole magnet (25); The third mini straight line section comprises a sixth horizontal focusing quadrupole magnet (26); The fourth mini straight line section comprises a sixth horizontal defocusing quadrupole magnet (16) and a second injection convex rail magnet (52) connected between the sixth horizontal defocusing quadrupole magnet (16) and the seventh deflection dipole magnet (7).

2. The medical proton synchrotron according to claim 1, characterized by The first mini straight line section further comprises a first horizontal focusing sextupole magnet (31) connected between the third horizontal focusing quadrupole magnet (23) and the third deflection dipole magnet (3); and the third mini straight line section further comprises a second horizontal focusing sextupole magnet (33) connected between the sixth horizontal focusing quadrupole magnet (26) and the seventh deflection dipole magnet (7).

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