Beam transmission system for proton helium ion treatment device
By using the circular beam flow method and the rotator method in the particle beam therapy device to match the beam flow, and rotating the rotating section and the rotating frame synchronously, the problems of asymmetry and debugging complexity in the beam flow transmission system are solved, and the problem of "asymmetry" and "are realized" is achieved More stable and efficient beam current transmission.
Patent Information
- Application Number
- CN202411403645.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-02-21
AI Technical Summary
In the existing particle beam therapy devices, the beam current transmission system is prone to asymmetry during the transmission process, which leads to difficulties in designing and processing of magnets. The point-to-point matching method requires multi-angle debugging, and the system stability is low.
A beam transmission system including a dispersion segment, a lateral matching segment, a transmission segment, a rotating segment, a fixed treatment segment and a rotating treatment segment are adopted to ensure the symmetry of the lateral parameters of the beam through the circular beam flow method and the rotator method. and the rotation section is synchronously rotated with the rotating frame to reduce the frequency of change of magnet parameters.
It effectively solves the asymmetry problem in the beam current transmission system, simplifies magnet design and processing, reduces the complexity and instability of the system debugging, and meets the beam current transmission needs of proton and helium ion therapy devices.
Smart Images
Figure CN119488678A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to particle beam dynamics, and more particularly to a beam transmission system for a proton helium ion therapy device. Background Art
[0002] Proton and heavy ion therapy is an important means of treating cancer and is widely used in clinical practice. 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. At present, the commonly used particle types for cancer treatment are 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, and is expected to achieve better results in treatment. However, helium ion therapy is still in the experimental stage. There are no commercial devices that use helium ions, let alone dedicated helium ion accelerators and treatment centers. Therefore, the development of helium ion therapy devices is urgently needed.
[0003] In particle beam therapy devices, heavier particles are generally compatible with lighter particles, so helium ion therapy devices are also compatible with protons.
[0004] In particle beam therapy devices, synchrotrons are the most commonly used accelerator type, and the beam from the synchrotron to the affected part of the tumor patient needs to be transmitted over a long distance and matched to the parameters required for treatment. For particle beam therapy, it is generally required that the lateral size of the beam is less than 10 mm when it reaches the isocenter of treatment. The parameters of the particles drawn from the synchrotron are seriously asymmetric in the two lateral directions (X and Y). Therefore, during the transmission process, it is easy to produce a situation where the beam size in one direction is too large, which is not conducive to the design and processing of the magnet: the aperture of the magnet must be larger than the beam size. The larger the aperture of the magnet, the more difficult it is to achieve a higher magnetic field strength and gradient. The aperture of the dipole magnet is affected by the beam size in the Y direction, and the aperture of the quadrupole magnet is affected by the beam size in both the X and Y directions.
[0005] In the existing particle beam therapy device beam transmission system, the matching method used is mostly point-to-point matching. In this method, the beam parameters are still asymmetric during the transmission process, so the cross-section is elliptical. For non-rotationally symmetric beams, different rotating frame angles have different corresponding parameters, so dozens of rotating frame angles need to be debugged, which is a cumbersome process. In addition, since each angle requires a set of magnet parameters, the stability of the entire system is low and is greatly affected by errors. Summary of the invention
[0006] In order to solve the problems of complicated processes in the above-mentioned prior art, the present invention provides a beam transmission system for a proton helium ion therapy device.
[0007] According to the present invention, a beam transmission system for a proton helium ion therapy device comprises a dispersive section, a transverse matching section, a transmission section, a rotating section, a fixed treatment section, a rotating treatment section and a distribution section, wherein the fixed treatment section extends into a fixed treatment room, the rotating treatment section extends into a rotating treatment room, the fixed treatment section and the rotating treatment section are respectively connected to the transmission section through the distribution section, and the magnet layout equivalent transmission matrices of the transmission section and the distribution section are unit matrices (1, 1), respectively, wherein the dispersive section, the transverse matching section and the transmission section are connected in sequence to provide circular beam method matching, and the transverse matching section matches the transverse parameters of the beam to be symmetrical; or the dispersive section, the transverse matching section, the rotating section and the transmission section are connected in sequence to provide rotator method matching, and the transverse matching section matches the transverse size of the beam to be smaller for subsequent control and transmission, the magnet layout equivalent transmission matrix of the rotating section is (1, -1), and the rotating section rotates synchronously with the rotating treatment section, and the rotation angle of the rotating section is half of the rotation angle of the rotating treatment section.
[0008] In a preferred embodiment, the lateral matching section includes 4 to 6 quadrupole magnets, which match the cross-section of the beam to a circle in the circular beam method and match the lateral size of the beam to a smaller size in the rotator method for ease of subsequent control and transmission.
[0009] In a preferred embodiment, the β of the exit beam of the lateral matching section in the rotator method is x ≤3m, β y Between 2m-30m.
[0010] In a preferred embodiment, the rotating section includes 4 to 6 quadrupole magnets that rotate synchronously with the rotating frame.
[0011] In a preferred embodiment, the de-dispersion section includes 2 to 6 dipole magnets to bend the beam trajectory to the correct direction; the de-dispersion section also includes 6 to 8 quadrupole magnets to change the dispersion of the beam drawn out from the synchrotron to zero.
[0012] In a preferred embodiment, the achromatic section matches the beam parameters to α x =α y =0;β x =β y .
[0013] In a preferred embodiment, the transmission section includes 4 to 6 quadrupole magnets.
[0014] In a preferred embodiment, the rotating treatment section includes 3 dipole magnets and 6 to 10 quadrupole magnets, so that when the beam is transmitted to the isocenter of treatment, the transverse cross-section is circular and has a size less than 10 mm.
[0015] In a preferred embodiment, the correction magnets in the rotating treatment segment are integrated into part of the quadrupole magnet.
[0016] In a preferred embodiment, the dipole magnets in the rotating treatment section use superconducting magnets with a magnetic field strength of up to 4 T / m.
[0017] The beam transmission system for a proton helium ion therapy device according to the present invention is applicable to the beam transmission system of protons and helium ions, and adopts the circular beam method and the rotator method for matching, thereby avoiding the problem that the point-to-point matching method of the prior art requires multi-angle debugging, and meets the requirements of particle beam therapy for beam parameters. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 1 is a schematic structural diagram of a beam transmission system for a proton helium ion therapy device according to Example 1 of the present invention.
[0019] Figure 2 1 is a schematic diagram of the structure of a beam transmission system for a proton helium ion therapy device according to Example 2 of the present invention. DETAILED DESCRIPTION
[0020] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.
[0021] The beam transmission system for a proton helium ion therapy device according to the present invention is used for a proton and helium ion therapy device, and mainly includes devices such as a vacuum tube, a dipole magnet, a quadrupole magnet, and a correction magnet, which are used to complete the transmission and matching of the beam, wherein the vacuum tube ensures that the beam moves in a vacuum and is used for the entire system, and both the dipole magnet and the quadrupole magnet are electromagnets, and the strength of the dipole magnet and the gradient of the quadrupole magnet can be adjusted in real time according to the type and energy of the particle beam. The beam transmission system according to the present invention can be used to transmit protons and helium ions at the same time, and can be divided into a circular beam method and a rotator method according to different ways of realizing the functions.
[0022] Example 1 Circular Beam Method
[0023] like Figure 1 As shown, the beam transmission system according to this embodiment includes an achromatic segment 1, a lateral matching segment 2, and a transmission segment 3 connected in sequence. In addition, the beam transmission system also includes a fixed treatment segment 4 extending into the fixed treatment room 10 and a rotating treatment segment 5 extending into the rotating treatment room 20, and the fixed treatment segment 4 and the rotating treatment segment 5 are connected to the transmission segment 3 through the distribution segment 6, respectively.
[0024] Among them, the de-dispersion section 1 is used to eliminate the dispersion of the beam. Since the dispersion of the beam is large when it is extracted from the synchrotron, it will cause obvious orbital deviation of the beam due to energy dispersion during the transmission process. Therefore, the dispersion needs to be eliminated at the beginning of the entire transmission system. In the de-dispersion section 1, the dipole magnet and the quadrupole magnet jointly complete the function of de-dispersion. The de-dispersion section 1 includes 2 to 6 dipole magnets, which are used to bend the beam orbit to the correct direction so that the subsequent transmission of the beam is mainly on a straight track. The de-dispersion section 1 also includes 6 to 8 quadrupole magnets, which are used to change the dispersion of the beam extracted from the synchrotron to 0. Specifically, the de-dispersion section 1 matches the beam's transverse (X, Y direction) ββ parameters (β in the beam Twiss parameters) to the same value and α is 0, that is, α x =α y =0;β x =β y The quadrupole magnet also focuses the beam and controls its lateral size, preventing the beam from hitting the tube wall and causing loss. In actual operation, due to factors such as mechanical assembly errors and device operation vibrations, the beam position may deviate, that is, the beam center is not on the designed center line of the beam transmission system. The de-dispersion section 1 arranges several correction magnets in the empty spaces of the dipole magnet and the quadrupole magnet to "correct" the beam position deviation.
[0025] Among them, the transverse matching section 2 is used to match the transverse parameters of the beam to be symmetrical. The transverse (X, Y direction) parameters of the beam drawn from the synchrotron are seriously asymmetric, and the de-dispersion section 1 cannot solve this problem well. Therefore, the beam size in one of the X and Y directions will become larger and larger after drift, which is not conducive to the design and processing of the quadrupole magnet, and will also affect the design of the subsequent dipole magnet. The transverse matching section 2 includes 4 to 6 quadrupole magnets. The focusing effect of the quadrupole magnet is used to strictly control the transverse Twiss parameters of the beam, adjust the transverse phase space of the beam to a positive ellipse, and balance the transverse emittance through the action of the scattering foil, that is, the emittance in the X and Y directions is consistent, and the beam cross section is circular. After the matching is completed, it is convenient for the subsequent magnet layout design. It should be understood that the transverse matching section 2 arranges a number of correction magnets in the vacant space of the quadrupole magnet to "correct" the beam position deviation.
[0026] The transmission section 3 is used to transmit the beam to a farther place to meet the layout requirements of particle beam therapy devices with different numbers of treatment rooms. The transmission section 3 includes 4 to 6 quadrupole magnets, and the equivalent transmission matrix of its magnet layout is the unit matrix (1, 1), which refers to the four-dimensional matrix form That is, the beam parameters are the same at the entrance and exit of the transmission section 3. In this way, the better beam parameters achieved by the lateral matching section 2 can be maintained, making the lateral size of the beam smaller. It should be understood that the transmission section 3 arranges several correction magnets in the empty space of the quadrupole magnet to "correct" the beam position deviation.
[0027] Among them, the number of fixed treatment segments 4, rotating treatment segments 5, and distribution segments 6 are determined by the type and number of treatment rooms, that is, the treatment device can be configured with a variety of treatment rooms, the number of fixed treatment segments 4 is consistent with the number of configured fixed treatment rooms 10, the number of rotating treatment segments 5 is also consistent with the number of configured rotating treatment rooms 20, and the number of distribution segments 6 is consistent with the total number of treatment rooms 10, 20.
[0028] The distribution section 6 includes 1 to 2 dipole magnets and 2 to 4 quadrupole magnets, which are used to deviate the beam from the transmission line to the treatment room 10, 20. The function of the distribution section 6 is to deflect the beam from the main transmission line to the treatment room direction. The total bending angle of the dipole magnet is between 45 degrees and 90 degrees. The role of the quadrupole magnet is similar to that of the transmission section 3, which is used to maintain the beam parameters. The overall transmission matrix implemented by the distribution section 6 is the unit matrix (1, 1). It should be understood that the distribution section 6 arranges a number of correction magnets in the empty spaces of the dipole magnets and the quadrupole magnets to "correct" the beam position deviation.
[0029] Among them, the fixed treatment section 4 includes 2 to 4 quadrupole magnets. The fixed treatment section 4 is determined according to the type and layout of the treatment room of the treatment device, and its function is to transmit the beam from the distribution section 6 to the treatment head. The fixed treatment section 4 is the last functional section before the beam reaches the treatment head, and the beam needs to be finally matched so that the beam meets the treatment requirements when it reaches the affected area, that is, the transverse cross-section is circular and the size is less than 10mm. It should be understood that the fixed treatment section 4 arranges a number of correction magnets in the empty space of the quadrupole magnet to "correct" the beam position deviation.
[0030] Among them, the rotating treatment section 5 includes 3 dipole magnets and 6 to 10 quadrupole magnets, which are used to transmit the beam to the isocenter of the treatment. The rotating treatment section 5 is also determined by the type and layout of the treatment room of the treatment device. Its function is to transmit the beam from the distribution section 6 to the treatment head. However, unlike the fixed treatment section 4, all magnets, vacuum tubes and corresponding accessories of the rotating treatment section 5 need to rotate with the rotating frame to achieve different beam trajectories and perform multi-angle treatment on the affected area. The dipole magnets in the rotating treatment section 5 use superconducting magnets, and their magnetic field strength can reach up to 4T / m. Superconducting magnets can reduce the size of the rotating frame, realize the miniaturization of the treatment device, and reduce the construction cost of the device. Similarly, the rotating treatment section 5 needs to make the final matching of the beam so that the beam meets the treatment requirements when it reaches the affected area, that is, the transverse cross-section is circular and the size is less than 10mm. In the rotating treatment section 5, the correction magnet is integrated in some quadrupole magnets, which can "correct" the beam position deviation.
[0031] Example 2 Rotator Method
[0032] like Figure 2 As shown, the beam transmission system according to this embodiment includes a dispersive section 1, a lateral matching section 2, a rotating section 30 and a transmission section 3 which are connected in sequence. In addition, the beam transmission system also includes a fixed treatment section 4 extending into the fixed treatment room 10 and a rotating treatment section 5 extending into the rotating treatment room 20. The fixed treatment section 4 and the rotating treatment section 5 are respectively connected to the transmission section 3 through the distribution section 6.
[0033] Among them, the achromatic segment 1, the transmission segment 3, the fixed treatment segment 4, the rotating treatment segment 5 and the distribution segment 6 are the same as those in Example 1, and are not described again here.
[0034] The lateral matching section 2 includes 4 to 6 quadrupole magnets, which are used to change the Twiss parameter β of the beam to a smaller value for subsequent control and transmission. x ≤3m, according to the beam size requirements, β y It can be adjusted within the range of 2-30m. Although the achromatic section 1 has preliminarily controlled the lateral size of the beam, due to the different beam emittances in the X and Y directions, the beam sizes in the two directions are different under the same ββ function. The larger the beam size, the larger the aperture of the magnet is required, which is not conducive to the design and processing of the magnet (when the magnetic field strength or gradient of the magnet is the same, the larger the aperture, the more difficult it is to achieve). The size of the beam can be controlled by its phase shift in the magnet structure. By selecting a reasonable phase shift, the lateral matching section 2 can ensure that the beam within a certain range can be controlled within the desired size.
[0035] The rotating section 30 includes 4 to 6 quadrupole magnets for matching with the rotating gantry section. The magnets of the rotating section 30 will rotate synchronously with the rotating gantry when the beam transmission system is running, and the rotation angle of the magnets of the rotating section is half of the rotation angle of the rotating gantry (i.e., the rotating treatment section 5). From the perspective of beam physics, the magnet structure of the rotating section 30 needs to realize a transmission matrix of (1, -1) {referring to the four-dimensional matrix The form is}, that is, the exit (x, x') is equal to the entrance (x, x'), and the exit (y, y') is opposite to the entrance (-y, -y'). Thus, through the calculation of the transfer matrix, it can be obtained that through the joint action of the two rotation matrices (the rotation of the rotating section 30 relative to the upstream and the rotation of the rotating frame relative to the rotating section 30), the result is the same as the result of the transfer matrix operation of the rotating section 30 (1, -1 above), that is, through the rotation of the rotating section 30, the influence of the rotation angle of the rotating frame on the beam can be eliminated, and the magnets on the rotating frame do not need to change with the rotation angle, which can reduce the difficulty of the layout design of the rotating frame magnets and improve the stability in actual operation. It should be understood that the rotating section 30 arranges a number of correction magnets in the vacant positions of the quadrupole magnets to "correct" the beam position deviation.
[0036] In this way, the beam transmission system according to the present invention adopts the circular beam method and the rotator method for matching, avoiding the problem that the point-to-point matching method of the prior art requires multi-angle debugging. In theory, there is no need to change the magnet parameters with the change of angle, which greatly reduces the instability caused by frequent changes in magnet parameters, meets the beam transmission requirements of proton and helium ion treatment devices, and can make the beam parameters meet the treatment needs in proton and helium ion treatment devices.
[0037] 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 beam transmission system for a proton helium ion therapy device, characterized in that: The beam transmission system includes an achromatic section, a lateral matching section, a transmission section, a rotation section, a fixed treatment section, a rotation treatment section and a distribution section. The fixed treatment section extends into the fixed treatment room, the rotating treatment section extends into the rotating treatment room, the fixed treatment section and the rotating treatment section are respectively connected to the transmission section through the distribution section, and the magnet layout equivalent transmission matrices of the transmission section and the distribution section are the unit matrix (1, 1), Among them, the achromatic segment, the lateral matching segment and the transmission segment are connected in sequence to provide circular beam method matching, and the lateral matching segment matches the lateral parameters of the beam to be symmetrical; or the achromatic segment, the lateral matching segment, the rotation segment and the transmission segment are connected in sequence to provide rotator method matching, and the lateral matching segment matches the lateral size of the beam to be smaller for subsequent control and transmission. The magnet layout equivalent transmission matrix of the rotation segment is (1, -1), and the rotation segment rotates synchronously with the rotation treatment segment, and the rotation angle of the rotation segment is half of the rotation angle of the rotation treatment segment.
2. The beam transmission system according to claim 1, characterized in that: The lateral matching section includes 4 to 6 quadrupole magnets, which match the cross-section of the beam to a circle in the circular beam method and match the lateral size of the beam to a smaller size in the rotator method for ease of subsequent control and transmission.
3. The beam transmission system according to claim 2, characterized in that: β of the exit beam at the lateral matching section in the rotator method x ≤3m, β y Between 2m-30m.
4. The beam transmission system according to claim 1, characterized in that: The rotating section includes 4 to 6 quadrupole magnets which rotate synchronously with the rotating frame.
5. The beam transmission system according to claim 1, characterized in that: The de-dispersion section includes 2 to 6 dipole magnets to bend the beam trajectory to the correct direction; the de-dispersion section also includes 6 to 8 quadrupole magnets to reduce the dispersion of the beam drawn out from the synchrotron to 0.
6. The beam transport system according to claim 5, characterized in that: The achromatic section matches the beam parameters to α x =α y =0;β x =β y .
7. The beam transport system according to claim 1, characterized in that: The transmission section includes 4 to 6 quadrupole magnets.
8. The beam transport system according to claim 1, characterized in that: The rotating treatment section includes 3 dipole magnets and 6 to 10 quadrupole magnets, so that the beam is transmitted to the isocenter of the treatment with a circular cross-section and a size less than 10 mm .
9. The beam delivery system according to claim 8, characterized in that: The correction magnets in the rotating treatment segment are integrated into part of the quadrupole magnet.
10. The beam delivery system according to claim 1, characterized in that: The dipole magnets in the rotating treatment section use superconducting magnets with a magnetic field strength of up to 4 T / m.