CN109224319B - Full superconducting proton treatment system - Google Patents

Abstract

The invention discloses an all-superconducting proton therapy system, comprising: a superconducting cyclotron, the superconducting cyclotron is used to generate a proton beam; a superconducting rotating therapy cabin is equipped next to the superconducting cyclotron; The superconducting rotary therapy chamber includes beamlines of the rotary therapy chamber. By adopting the above technical solution, the proton therapy system adopts the mode of superconducting cyclotron equipped with superconducting rotating therapy cabin. The system has a compact layout, occupies a small space, and greatly reduces the weight of the equipment, which further reduces the Manufacturing costs, that is, the present invention provides a solution for a fully superconducting proton therapy system for reducing the size, weight, and manufacturing costs of proton therapy equipment.

Description

Fully superconducting proton therapy system

technical field

The invention relates to the technical field of proton therapy, and also belongs to the biological (medical) technical field, in particular to an all-superconducting proton therapy system.

Background technique

At present, the incidence of cancer in my country is getting higher and higher, and it has become one of the biggest killers that endanger the health of our people. The usual treatment methods include surgery, gamma knife, proton/heavy ion therapy, etc.

The proton/heavy ion therapy mainly uses an accelerator to generate a proton/heavy ion beam with a certain energy, and transmits the beam to the target area through various electromagnetic elements to bombard tumor cells to achieve the therapeutic effect. Since protons have sharp Bragg peaks in substances, that is, their energy will be lost to the cancerous position to the greatest extent, so they can kill cancerous cells and protect normal tissues to the greatest extent, which makes proton therapy the most advanced in the world. It is one of the treatment methods for malignant tumors, and it is also one of the popular treatment methods in the world.

Proton therapy systems usually consist of major subsystems such as accelerators, energy selection and beam delivery systems, and rotating or fixed treatment cabins. The normal temperature proton cyclotron weighs about 200 tons and has a diameter of about 4.5 meters. The volume of the synchrotron is larger. The superconducting cyclotron weighs only 50 to 90 tons and has a diameter of 2 to 3.2 meters. The normal temperature rotary therapy gantry system needs at least 100 tons (100 tons to 200 tons), and the superconducting rotary therapy cabin system is about 20 tons. The most common proton therapy systems in the world are normal temperature accelerators equipped with normal temperature rotary therapy cabins (such as IBA's normal temperature C235 cyclotron equipped with normal temperature Proteusplus rotary therapy chambers), superconducting accelerators equipped with normal temperature rotary therapy chambers (such as IBA's S2C2 superconducting synchrocyclotrons). Equipped with Proteus one rotary therapy cabin, PSI/Varian superconducting cyclotron equipped with normal temperature rotary therapy chamber), normal temperature accelerator equipped with superconducting rotary therapy chamber (such as HIMAC-NIRS normal temperature heavy ion synchrotron equipped with superconducting rotary therapy chamber, normal temperature proton cyclotron) With Pronova SC360 superconducting rotating therapy cabin), there is no fully superconducting proton therapy system yet, which causes the current proton therapy system still has the problems of large size, excessive weight and high manufacturing cost.

Take PSI's 250MeV superconducting cyclotron plus room temperature rotating treatment cabin solution as an example, because its accelerator uses superconducting coils to excite the main magnet, compared with the main magnet of the room temperature cyclotron, the air gap of the magnetic pole is larger, on the one hand, there is enough space The installation of the flow intensity modulation device can realize the rapid modulation of the flow intensity of the proton beam, and then realize the proton intensity modulated therapy, which can control the treatment dose of the patient more precisely. On the other hand, the proton beam extraction efficiency is high, and the beam loss is small. ; And the use of superconducting coils makes the electric power of the main magnet (including the power of the refrigerator) only ~50kW, which is about 1/4 of the normal temperature gyroscopic main magnet, which is energy-saving and environmentally friendly. The matching of the accelerator and the rotating treatment cabin is also very important for the final performance. In proton therapy, the advanced fast-scan treatment technology of tumor layers requires rapid changes in proton energy, which in turn requires the magnetic field of the magnet on the rotating treatment cabin for constraining proton trajectories to respond accordingly. of rapid changes. In order to achieve fast layered scanning, the beam transmission line of PSI’s rotating treatment cabin uses a normal temperature magnet to achieve rapid changes in the magnetic field. Therefore, it can achieve fast proton energy changes with only ~100ms switching time per 5mm treatment depth. The cost of the proton therapy system with the fastest treatment speed is the rotating therapy cabin weighing nearly 200 tons. The entire proton therapy system is large in scale, and the power consumption of the room temperature magnet therapy cabin cannot be reduced.

At present, the primary technical difficulty of the superconducting rotary therapy cabin is how to adapt to the rapid change of proton energy required by the tumor stratified fast scanning therapy technology. Since the current superconducting magnets cannot achieve the rapid magnetic field changes like normal temperature magnets, either the scanning speed of the superconducting rotating treatment cabin is slow (NIRS-HIMAC), or the design of the achromatic bending section is used to increase the The momentum acceptance of the superconducting rotating therapy cabin makes the protons within the range of 0-30cm of the human body. When changing the scanning depth, only a certain working point of the excitation current of the superconducting magnet needs to be set, and each working point can cover the nearby protons. There is no need to adjust the excitation current of the superconducting magnet; only after the range exceeds the coverage of each operating point, the excitation current of the superconducting magnet can be adjusted to the next operating point. The latter method is a good idea, but on the one hand, there is a limit to how to optimize the momentum acceptance under a fixed magnetic field. On the other hand, the switching process at the operating point is still limited by the excitation rate of the superconducting magnet, which takes time. The scanning speed of the superconducting rotary therapy cabin still cannot exceed the PSI room temperature rotary therapy cabin design. In order to improve the scanning speed of the superconducting treatment cabin, it is necessary to optimize the structure or material of the superconducting magnet to prevent eddy currents and quench protection.

SUMMARY OF THE INVENTION

In view of the above technical problems, the purpose of the present invention is to provide a fully superconducting proton therapy for improving the scanning speed of the superconducting therapy cabin and reducing the size, weight and manufacturing cost of the proton therapy equipment without affecting the proton therapy effect. system plan.

For achieving the above object, the invention provides the following technical solutions: a full superconducting proton therapy system, comprising:

a superconducting cyclotron for generating a proton beam;

The superconducting cyclotron is equipped with a superconducting rotary therapy cabin;

The superconducting rotating treatment cabin includes beam lines of the rotating treatment cabin.

By adopting the above technical solution, the proton therapy system adopts the mode of superconducting cyclotron equipped with superconducting rotating therapy cabin. The system has a compact layout, occupies a small space, and greatly reduces the weight of the equipment, which further reduces the Manufacturing costs. Compared with the normal temperature cyclotron, the superconducting cyclotron and the superconducting rotating beamline magnet are more energy-saving, environmentally friendly and significantly reduce the operating cost than the normal temperature rotating beamline magnet.

The present invention is further provided as follows: a beam transport system and an energy selection system are sequentially arranged between the superconducting cyclotron and the superconducting rotating treatment cabin in the direction of the beam output generated by the superconducting cyclotron.

By adopting the above technical solution, the beam transport system is used to transmit the beam, and let the beam enter the energy selection system for energy selection and elimination of chromatic aberration, thereby improving the quality of the beam transmitted to the rotating treatment cabin.

The present invention further provides that: the beam transport system includes a first quadrupole lens group and an energy reducer arranged in sequence.

By adopting the above technical solution, the first quadrupole lens group is used to focus the beam drawn from the superconducting cyclotron, and the focused beam then enters the energy reducer for energy adjustment.

The present invention further provides that: the energy selection system includes a first deflection magnet, a second quadrupole lens and a second deflection magnet which are arranged in sequence.

By adopting the above technical solution, the first deflection magnet is used for deflecting the beam current drawn from the superconducting cyclotron, and the second quadrupole lens is used for focusing the beam current after passing through the first deflection magnet, The second deflection magnet is used for deflecting the beam after passing through the second quadrupole lens, thereby realizing energy selection of the beam and eliminating chromatic aberration.

The present invention further provides that: the beam transport system further comprises a third quadrupole lens, a third deflection magnet, a fourth quadrupole lens, a fourth deflection magnet and a fifth quadrupole lens which are arranged in sequence.

By adopting the above technical solution, the third quadrupole lens is used for focusing the beam after passing through the second deflection magnet, and the third deflection magnet is used for focusing the beam after passing through the third quadrupole lens The fourth quadrupole lens is used for focusing the beam current after passing through the third deflection magnet, and the fourth deflection magnet is used for focusing the beam current after passing through the fourth quadrupole lens. Deflection, the fifth quadrupole lens is used for focusing the beam current after passing through the fourth deflection magnet, thereby realizing the transmission of the beam current and controlling the quality of the beam current during the transmission process.

The present invention further provides that: a diagnostic element 1 is arranged between the second deflection magnet and the third quadrupole lens.

By adopting the above technical solution, a diagnostic element 1 is disposed between the second deflection magnet and the third quadrupole lens. In this way, the beam current passing through the second deflection magnet can be detected by the diagnostic element one.

The present invention is further provided as follows: the superconducting rotating treatment cabin includes a fifth deflection magnet, a sixth quadrupole lens and a sixth deflection magnet arranged in sequence, and the fifth deflection magnet, the sixth quadrupole lens and the sixth deflection magnet arranged in sequence Six deflection magnets constitute the beam line of the rotating treatment cabin.

By adopting the above technical solution, the fifth deflection magnet is used for deflecting the beam after passing through the fifth quadrupole lens, and the sixth quadrupole lens is used for deflecting the beam after passing through the fifth deflection magnet The beam is focused, and the sixth deflection magnet is used for deflecting the beam after passing through the sixth quadrupole lens.

The present invention further provides that: a second diagnostic element is arranged between the sixth quadrupole lens and the sixth deflection magnet.

By adopting the above technical solution, the second diagnostic element is arranged between the sixth quadrupole lens and the sixth deflection magnet. In this way, the beam current passing through the sixth quadrupole lens can be detected by the second diagnostic element.

The present invention further provides that: the fifth deflection magnet, the sixth quadrupole lens and the sixth deflection magnet 16 are all superconducting magnets.

By adopting the above technical solution, the fifth deflection magnet, the sixth quadrupole lens and the sixth deflection magnet are all superconducting magnets. The superconducting magnet has high field strength, compact structure and light weight. The efficiency and stability of the extracted beam are further improved.

To sum up, the present invention has the following beneficial effects:

The occupied space and weight of the proton therapy equipment are greatly reduced, so that the requirements for the plant space and load-bearing of the proton therapy equipment are significantly reduced, and the construction cost of the proton therapy device and the power consumption of the equipment are significantly reduced, which solves the problem of the existing proton therapy system. The problems of huge equipment and high requirements on plant space and load-bearing make the proton therapy system solution of the present invention can perform one-to-one replacement of the existing traditional X-ray therapy equipment with huge installed capacity.

Description of drawings

FIG. 1 is a schematic structural diagram of the all-superconducting proton therapy system of the present invention.

Reference numerals: 1. Superconducting cyclotron; 2. The first quadrupole lens group; 3. The energy reducer; 4. The first deflection magnet; 5. The second quadrupole lens; 6. The second deflection magnet; 7. Diagnostic element 1; 8, the third quadrupole lens; 9, the third deflection magnet; 10, the fourth quadrupole lens; 11, the fourth deflection magnet; 12, the fifth quadrupole lens; 13, the fifth deflection magnet; 14 , the sixth quadrupole lens; 15, the second diagnostic element; 16, the sixth deflection magnet; 17, the treatment head.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings.

As shown in Figure 1, the all-superconducting proton therapy system includes: a superconducting cyclotron 1, which is used to generate a beam; when the superconducting cyclotron 1 is a superconducting proton cyclotron, the superconducting cyclotron 1 1 is used to generate a proton beam; the superconducting cyclotron 1 is equipped with a superconducting rotating treatment cabin; the superconducting rotating treatment cabin includes the beam line of the rotating treatment cabin and its superconducting magnet. Different from the commonly used proton therapy schemes, the normal temperature accelerator is equipped with a superconducting rotary therapy chamber, the normal temperature accelerator is equipped with a normal temperature rotary therapy chamber, and the superconducting cyclotron is equipped with a normal temperature rotary therapy chamber. The proton therapy system proposed here uses a superconducting cyclotron. The accelerator is equipped with a superconducting rotary therapy cabin. The system has a compact layout, takes up little space, and greatly reduces the weight of the equipment. Compared with the normal temperature cyclotron, the superconducting cyclotron and the superconducting rotating beamline magnet are more energy-saving, environmentally friendly and significantly reduce the operating cost than the normal temperature rotating beamline magnet.

In the output direction of the beam generated by the superconducting cyclotron 1 and between the superconducting cyclotron 1 and the superconducting rotating treatment cabin, a beam transport system and an energy selection system are sequentially arranged. The beam transport system is used to transport the beam and let the beam enter the energy selection system for energy selection and chromatic aberration elimination. When the superconducting cyclotron 1 is a superconducting proton cyclotron, the beam transport system is used to transport the proton beam, and let the proton beam enter the energy selection system for energy selection and chromatic aberration elimination.

The beam transport system includes a first quadrupole lens group 2 and a de-energizer 3 arranged in sequence; the first quadrupole lens group 2 is used for focusing the beam current drawn from the superconducting cyclotron 1, and the focused beam current is subsequently Enter the energy reducer 3 for energy adjustment; the first quadrupole lens group 2 is arranged in the direction of the beam current drawn from the superconducting cyclotron 1; the energy reducer 3 is arranged in the direction of the beam current after passing through the first quadrupole lens group 2 superior.

The energy selection system includes a first deflection magnet 4, a second quadrupole lens 5 and a second deflection magnet 6 arranged in sequence; the first deflection magnet 4 is used to deflect the beam current drawn from the superconducting cyclotron 1, and the second quadrupole lens 5 It is used to focus the beam after passing through the first deflection magnet 4, and the second deflection magnet 6 is used to deflect the beam after passing through the second quadrupole lens 5. In the direction of the beam after passing through the second quadrupole lens 5, the second quadrupole lens 5 is arranged in the direction of the beam after passing through the first deflection magnet 4, and the second deflection magnet 6 is arranged in the direction of the beam passing through the second quadrupole lens 5. .

The beam transport system also includes a third quadrupole lens 8, a third deflection magnet 9, a fourth quadrupole lens 10, a fourth deflection magnet 11 and a fifth quadrupole lens 12 arranged in sequence; For focusing the beam passing through the second deflection magnet 6, the third deflection magnet 9 is used for deflecting the beam passing through the third quadrupole lens 8, and the fourth quadrupole lens 10 is used for deflecting the beam passing through the third quadrupole lens 8. The beam after the magnet 9 is focused, the fourth deflection magnet 11 is used to deflect the beam after passing through the fourth quadrupole lens 10 , and the fifth quadrupole lens 12 is used to deflect the beam after passing through the fourth deflection magnet 11 For focusing, the third quadrupole lens 8 is arranged in the direction of the beam after passing through the second deflection magnet 6, the third deflection magnet 9 is arranged in the direction of the beam after passing through the third quadrupole lens 8, and the fourth and fourth The pole lens 10 is arranged in the direction of the beam after passing through the third deflection magnet 9, the fourth deflection magnet 11 is arranged in the direction of the beam after passing through the fourth quadrupole lens 10, and the fifth quadrupole lens 12 is arranged in the direction of the beam passing through the fourth quadrupole lens 10. The direction of the beam current after the fourth deflection magnet 11.

A diagnostic element 1 7 is arranged between the second deflection magnet 6 and the third quadrupole lens 8 . In this way, the beam current passing through the second deflection magnet 6 can be detected by the diagnostic element 1 . The first diagnostic element is a beam detection device.

The superconducting rotating treatment cabin is set in the treatment room and includes a fifth deflection magnet 13, a sixth quadrupole lens 14 and a sixth deflection magnet 16 arranged in sequence, and the fifth deflection magnet 13, the sixth quadrupole lens 14 and The sixth deflection magnet 16 constitutes the beam line of the rotating treatment cabin; the fifth deflection magnet 13 is used to deflect the beam after passing through the fifth quadrupole lens 12, and the sixth quadrupole lens 14 is used to deflect the beam passing through the fifth quadrupole lens 14. The beam after the deflection magnet 13 is focused, the sixth deflection magnet 16 is used to deflect the beam after passing through the sixth quadrupole lens 14 , and the fifth deflection magnet 13 is arranged on the beam after passing through the fifth quadrupole lens 12 The sixth quadrupole lens 14 is arranged in the direction of the beam after passing through the fifth deflection magnet 13, the sixth deflection magnet 16 is arranged in the direction of the beam after passing through the sixth quadrupole lens 14, and the treatment head 17 is arranged in the direction of the beam current after passing through the sixth deflection magnet 16 .

The second diagnostic element 15 is disposed between the sixth quadrupole lens 14 and the sixth deflection magnet 16 . In this way, the beam current passing through the sixth quadrupole lens 14 can be detected by the second diagnostic element. The second diagnostic element is a beam detection device.

The fifth deflection magnet 13, the sixth quadrupole lens 14 and the sixth deflection magnet 16 are all superconducting magnets. The superconducting magnet has high field strength, compact structure and light weight.

The beam extracted from the superconducting proton accelerator 1, the beam is then transported in the beam transport system, firstly focused by the first quadrupole lens group 2, and adjusted by the energy reducer 3, and then by the first deflection magnet 4. The second deflection magnet 6 and the second quadrupole lens 5 perform energy selection and eliminate chromatic aberration, and pass through the third quadrupole lens 8, the fourth quadrupole lens 10, the fifth quadrupole lens 12, the third deflection magnet 9, The fourth deflection magnet 11 is transmitted to the rotating treatment room, and the beam line of the rotating treatment cabin composed of the fifth deflection magnet 13, the sixth deflection magnet 16 and the sixth quadrupole lens 14 finally sends the beam to the treatment head. Such an all-superconducting system reduces the overall size and weight of the device, and improves the efficiency and stability of the beam extracted from the accelerator.

Compared with the normal temperature cyclotron, the weight of the superconducting cyclotron is about 1/2 of the normal temperature cyclotron, and the diameter is about 2/3 or even 1/2 of the normal temperature cyclotron, and the volume and weight have been greatly reduced. In addition, the superconducting cyclotron uses superconducting coils, and the air gap between the magnetic poles is large, which is convenient for the installation and maintenance of equipment such as high-frequency cavity, beam diagnosis, extraction system, etc., with high reliability and extraction efficiency higher than that of the room temperature cyclotron.

Compared with the normal temperature rotary treatment cabin, the weight of the superconducting rotary treatment cabin can be 1/10 of the weight of the normal temperature rotary treatment cabin, and the diameter and length are also lower than those of the normal temperature rotary treatment cabin, which is extremely beneficial to the hospital. . Moreover, it is different from the existing superconducting rotating treatment cabin design of normal temperature quadrupole magnet + superconducting deflection magnet, which adopts the design of full superconducting rotating treatment cabin, that is, the quadrupole magnet for focusing and the dipole magnet for deflection use superconducting rotating treatment cabin design. Conductive magnet design.

In addition, the tumor layered scanning requires rapid changes in energy, which in turn need to rotate the magnetic field of the magnet on the treatment cabin to perform corresponding rapid changes. When the magnetic field of the superconducting magnet changes rapidly, an induced voltage will be induced at the low temperature system end of the magnet, and the low temperature system will be loaded by this voltage. On end metal structures, such as cold shields, liquid helium tanks, etc., eddy currents are generated, and this part of the energy will cause structural damage to the cryogenic system (cold shields are distorted, resulting in conduction heat across the cold shield temperature and the liquid helium temperature), and Resistive heat load at the low temperature end (eddy current heat generation), resulting in low temperature failure, which in turn causes the coil to quench. To solve this problem, a structure for blocking the eddy current can be used to block the eddy current, or a material with higher resistivity can be used to reduce the eddy current. The rapid change of the magnetic field of the superconducting magnet causes the voltage L*di/dt across the superconducting coil, where L is the inductance value of the superconducting coil, i is the current passing through the superconducting coil, and t is the moment of the current i passing through the superconducting coil In this case, usually in the field of MRI superconducting magnets, multiple cold diode groups connected in parallel in back-to-back are connected in series, and then connected at both ends of the coil for quench protection, which will seriously limit the speed of magnetic field change of the superconducting magnet and affect tumor differentiation. Layer scan speed. In order to solve this problem, quench protection can be performed by means of superconducting coils such as high copper superconducting ratios without adding additional cold diodes. In this way, the superconducting magnet quench protection circuit on the rotating bracket is reasonably selected, so that the voltage across the coil generated by the rapidly changing magnetic field can be accommodated, and the maximum temperature of the coil is not too high. Increased the scan speed of the superconducting therapy cabin.

This specific embodiment is only an explanation of the present invention, and it does not limit the present invention. Those skilled in the art can make modifications without creative contribution to the present embodiment as required after reading this specification, but as long as the rights of the present invention are used All claims are protected by patent law.

Claims (6)

1. A fully superconducting proton therapy system, comprising: the device comprises a superconducting cyclotron (1), a control unit and a control unit, wherein the superconducting cyclotron (1) is used for generating proton beams; a superconducting rotary treatment cabin capable of adapting to the rapid change of a superconducting magnet magnetic field on the rotary treatment cabin is arranged beside the superconducting cyclotron (1);

the superconducting rotary treatment cabin comprises a beam streamline of the rotary treatment cabin; the superconducting rotary treatment cabin comprises a fifth deflection magnet (13), a sixth quadrupole lens (14) and a sixth deflection magnet (16) which are sequentially arranged, and the fifth deflection magnet (13), the sixth quadrupole lens (14) and the sixth deflection magnet (16) which are sequentially arranged form a beam line of the rotary treatment cabin; the fifth deflection magnet (13), the sixth quadrupole lens (14) and the sixth deflection magnet (16) are all superconducting magnets;

the superconducting rotary treatment cabin adopts a structure for blocking eddy current or adopts a component made of a material with higher resistivity to reduce the eddy current, so as to solve the problem that the eddy current on a low-temperature system generates heat and further causes quench due to the rapid change of current; the superconducting rotary treatment cabin also adopts a high-copper-to-superconducting coil to solve the problem that the voltage between the superconducting coils can be increased due to the rapid change of current, so that a cold diode cannot be adopted for quench protection.

2. The fully superconducting proton therapy system according to claim 1, wherein: a beam transport system and an energy selection system are sequentially arranged in the beam output direction generated by the superconducting cyclotron (1) and between the superconducting cyclotron (1) and the superconducting rotary therapy cabin.

3. The fully superconducting proton therapy system according to claim 2, wherein: the beam transport system comprises a first quadrupole lens group (2) and an energy degrader (3) which are sequentially arranged.

4. The fully superconducting proton therapy system according to claim 2, wherein: the energy selection system comprises a first deflection magnet (4), a second quadrupole lens (5) and a second deflection magnet (6) which are arranged in sequence; the beam transport system further comprises a third quadrupole lens (8), a third deflection magnet (9), a fourth quadrupole lens (10), a fourth deflection magnet (11) and a fifth quadrupole lens (12) which are sequentially arranged.

5. The fully superconducting proton therapy system according to claim 4, wherein: a first diagnostic element is arranged between the second deflection magnet (6) and the third quadrupole lens (8).

6. The fully superconducting proton therapy system according to claim 1, wherein: a second diagnostic element (15) is arranged between the sixth quadrupole lens (14) and the sixth deflection magnet (16).

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