WO2020093608A1

WO2020093608A1 - Shielding apparatus for proton therapy system

Info

Publication number: WO2020093608A1
Application number: PCT/CN2019/073198
Authority: WO
Inventors: 汪金龙; 郑志鸿; 刘铮铮; 李凯若
Original assignee: 新瑞阳光粒子医疗装备(无锡)有限公司
Priority date: 2018-11-07
Filing date: 2019-01-25
Publication date: 2020-05-14

Abstract

A shielding apparatus for a proton therapy system. The shielding apparatus is a multi-compartment structure comprising a synchrotron compartment and a rotatable gantry compartment. The synchrotron compartment is in communication with the rotatable gantry compartment. The rotatable gantry compartment comprises an upper rotatable gantry compartment section, a lower rotatable gantry compartment section, and a gantry recess formed between the upper rotatable gantry compartment section and the lower rotatable gantry compartment section. The upper rotatable gantry compartment section is configured to be in communication with the synchrotron compartment.

Description

Shield for proton therapy system

This application requires the priority of the Chinese patent application with the application date of November 07, 2018, application number 201811317523.3 and application date of November 07, 2018, application number 201821825482.4. The entire content of the application is incorporated by reference in this document Applying.

Technical field

The present disclosure relates to the technical field of radiation protection, for example, to a shield used in a proton therapy system.

Background technique

Proton therapy is recognized worldwide as the most effective tumor treatment method with the least side effects, and having a 360-degree rotating gantry allows the proton beam to accurately bombard the patient from multiple angles according to the optimal path without moving the patient The location of the tumor is less time-consuming and less harmful to healthy tissues, while enabling proton therapy technology to be applied to more types of tumor treatment.

During the accelerated rotation of protons, a large amount of particle radiation harmful to public health will be generated. Based on the principle of radiation protection optimization, the builder of the proton therapy system should minimize the radiation generated by the proton therapy system to reduce the impact on the public and the environment.

The proton therapy system with a rotating gantry in the related art is usually installed in a large building made of concrete; however, the radiation shield of this proton therapy system cannot be conformally designed according to the radiation dose of the therapy system, but is over For protection, the shield body is as large and thick as possible to reduce radiation, so that the shield body occupies a large space and the construction cost is high. The type and thickness of the shielding material determine the cost. With the development of miniaturization of synchrotrons, it is urgent for commercial medical proton therapy systems to design an economical, safe, and effective shielding body.

Summary of the invention

The present disclosure provides a shielding body for a proton therapy system, which can perform targeted shielding against the radiation of the proton therapy system to achieve the best protection, while saving costs and reducing space occupation.

A shielding body for a proton therapy system, wherein the shielding body is a multi-chamber structure constructed by a shielding wall, the shielding body includes a synchrotron chamber and a rotating gantry chamber, the synchrotron chamber and the rotation The rack rooms communicate with each other; the rotating rack room includes an upper rotating rack room, a lower rotating rack room, and a rack slot opened between the upper rotating rack room and the lower rotating rack room. The upper rotating frame chamber is located at an upper part of the lower rotating frame chamber, and the upper rotating frame chamber is arranged to communicate with the synchrotron chamber and form a cavity.

Brief description of the drawings

1 is a schematic structural diagram of a proton therapy system provided in Example 1;

FIG. 2 is a schematic structural view of each chamber of the shielding body provided in Embodiment 2 cut away;

3 is a dose distribution diagram of the intermediate cross-section of the shielding body provided in Embodiment 2;

4 is a dose distribution diagram on the middle longitudinal section of the shielding body provided in Embodiment 2;

5 is a schematic structural view of each chamber of the shielding body provided in Embodiment 3 cut away;

6 is a dose distribution diagram of the intermediate cross section of the shielding body provided in Embodiment 3;

7 is a dose distribution diagram on the middle longitudinal section of the shield provided by the third embodiment;

8 is a radiation dose distribution diagram of the proton therapy system in the case of setting different shielding walls in the fourth embodiment;

9 is a schematic diagram of the function of scanning the treatment head and the target body in the fourth embodiment.

In the picture:

1-Proton therapy system;

11-injector; 12-synchrotron; 13-extraction device; 14-rotating gantry; 15-scanning treatment head;

2- target body;

3. 3′-shield body;

31, 31 '-synchrotron room; 32, 32'-rotating frame room; 321, 321 '-upper rotating frame room; 322, 322'-lower rotating frame room; 323, 323 '-frame slot; 33, 33′-treatment room; 34, 34′-maze room; 35, 35′-equipment room;

4- concrete layer; 5- iron material layer.

detailed description

Example one

This embodiment provides a shield for a proton therapy system. As shown in FIG. 1, the proton therapy system 1 is a 360 ° rotating gantry proton therapy system, which includes an injector 11 and a synchrotron 12 connected in sequence. The extraction device 13, the rotating gantry 14 and the scanning treatment head 15. The protons are injected into synchrotron 12 by injector 11 and accelerated by synchrotron 12 to obtain energy to form a proton beam. The proton beam is guided by the magnet of the extraction device 13 to the rotating frame 14 through the three of the rotating frame 14 After a two-pole magnet is emitted from the scanning treatment head 15 to the target body 2 (ie, the lesion of the patient), the treatment is completed. Among them, the proton beam will cause a large beam loss on the two-pole magnet of the synchrotron 12, the three-pole magnet of the extraction magnet and the rotating gantry 14, and the scanning treatment head 15, resulting in strong radiation energy, so In the design of radiation shields, it is necessary to focus on the radiation protection in these areas.

As shown in FIG. 2, the shield body 3 is a multi-chamber structure constructed by a shield wall as a whole, including a synchrotron room 31, a rotating gantry room 32, a treatment room 33, a labyrinth room 34 and an equipment room 35. Among them, the injector 11, synchrotron 12 and extraction device 13 are arranged in the synchrotron chamber 31, the rotating frame 14 is arranged in the rotating frame chamber 32, the scanning treatment head 15 and the target body 2 are located in the treatment room 33, the equipment room 35 is set to place electrical equipment of the proton therapy system 1.

The synchrotron chamber 31 and the rotating gantry chamber 32 communicate with each other, and do not have any shielding structure, forming a whole chamber. This arrangement can save space and also reduce the waste of shielding materials. In addition, because the rotating frame 14 occupies a large space in the vertical direction, the rotating frame chamber 32 can be divided into an upper upper rotating frame chamber 321 and a lower lower rotating frame chamber 322, the upper rotating frame chamber 321 and the lower A rack slot 323 is provided between the rotating rack chambers 322, and the rotating rack 14 is disposed through the rack slot 323; the shape and structure of the rack slot 323 are designed according to the structure of the rotating rack 14 to avoid excessive radiation The lower rotating rack chamber 322 penetrates. The upper rotating frame chamber 321 and the synchrotron chamber 31 communicate with each other.

There is a partition wall (not shown in the figure) between the rotating gantry room 32 and the treatment room 33. The partition wall can be a simple wall structure, which can be made of insulating materials such as wooden boards and plastic boards instead of concrete The manufacturing, that is, the separation wall only needs to isolate the treatment room 33 and the rotating gantry room 32. The isolation design of the rotating gantry room 32 and the treatment room 33 can save the manufacturing cost of the shield body and avoid the waste of excessive shielding materials.

The labyrinth room 34 is disposed on one side of the upper rotating gantry room 321, and communicates with the treatment room 33, so that the operator can enter the treatment room 33 from the labyrinth to help the patient to perform positioning and treatment. The labyrinth room 34 is provided with a labyrinth entrance and a labyrinth exit. The labyrinth entrance is located outside the labyrinth and communicates with the outside world. The labyrinth exit and the treatment room 33 are interconnected. .

The equipment room 35 is provided below the labyrinth room 34 and is located on one side of the lower rotating gantry room 322. The entire proton therapy system 1 electrical equipment is placed in the equipment room 35. The equipment 35 room and the lower rotating gantry room 322 are mutually connected. Connected and set to connect electrical equipment to multiple components of the proton therapy system 1.

The rotating gantry chamber 32 and the synchrotron chamber 31 of this embodiment communicate with each other without a shielding wall, and a separating wall (not a shielding wall) is provided between the rotating gantry chamber 32 and the treatment room 33, which reduces the construction of the shielding body 3 Cost; in this embodiment, the shielding body 3 is designed with a conformal structure and thickness, so that the shielding body 3 can achieve the protection purpose with the smallest space, and also saves the construction cost, which is beneficial to commercial promotion; the shielding body of this embodiment 3. The use of concrete and iron materials as shielding materials can further reduce the thickness setting of the shielding body 3 and reduce the space occupied by the shielding body 3.

Example 2

The shielding body 3 as described in the first embodiment, the shielding wall of the shielding body 3 is a concrete layer 4, the height and volume of each chamber are designed according to the structure size of each part of the proton therapy system 1, but this embodiment can The lower limit value of the specific wall thickness dimension of the shield body 3 is provided, and the lower limit value is conformally set according to the maximum radiation amount when the proton therapy system 1 located in the shield body 3 is used.

As shown in the coordinate system in FIG. 2, the up or down direction in this embodiment is the Z-axis direction, the left or right direction is the Y-axis direction, and the front or back direction is the X-axis direction for easy understanding. .

In an embodiment, the thickness of the upper wall and the lower wall of the synchrotron chamber 31 are set to 2m, and the thickness of the left wall of the synchrotron chamber 31 is set to 2m, where the thickness of the lower part of the left wall can be thickened to 3m for more safety Shielding effect.

The thickness of the lower wall of the upper rotating rack chamber 321 is also set to 2m, the thickness of the upper wall is 3m, the thickness of the right wall is set to 2m, and the right wall of the upper rotating rack chamber 321 is set to isolate the upper rotating rack chamber 321 and the labyrinth chamber 34 ; Among them, the thickness of the part of the right wall near the rear side is set to 3m.

In an embodiment, the thicknesses of the entire synchrotron chamber 31, the front wall of the upper rotating frame chamber 321, and the rear wall of the upper rotating frame chamber 321 are all set to 3 m.

The upper wall of the lower rotating frame chamber 322 is the lower wall of the upper rotating frame chamber 321, and the thickness of the side wall, front wall and rear wall of the lower rotating frame chamber 322 is 2m, and the thickness of the lower wall is 3m.

The thickness of the upper wall, the lower wall, the right wall, and the rear wall of the labyrinth chamber 34 are all set to 1 m, and the thickness of the front wall of the labyrinth chamber 34 is set to 2 m.

In order to further enhance the radiation resistance of the upper rotating frame chamber 321, a layer of shielding wall is added on the outer side of the right wall of the upper rotating frame chamber 321, the shielding wall is located above the labyrinth chamber 34, and the thickness is set to 0.5m.

The upper wall of the equipment room 35 is the lower wall of the labyrinth room 34. The equipment room 35 and the lower rotating rack room 322 are separated by the right wall of the lower rotating rack room 322, and the front wall, rear wall, and lower wall of the equipment room 35 The thickness of the right wall is 0.5m.

Regarding the radiation dose standard, the requirements of the national standard GB18871-2002 are: occupational exposure annual dose is less than 20 mSv, and public exposure annual dose is less than 1mSv. The design goal of the shielding body 3 provided in this embodiment is that the annual dose of occupational exposure is less than 5mSv, which is 1/4 of the national standard, and the annual dose of public exposure is less than 0.1mSv, which is 1/10 of the national standard, as shown in Table 1:

Table 1 Radiation dose standard (unit: mSv / year)

According to the specific wall thickness design of the above shielding body 3, a simulation analysis of the radiation amount distribution of the shielding body 3 is performed according to the Monte Carlo algorithm, and it is verified that the design of the structure and thickness of the shielding body 3 of the present embodiment can meet the requirements of radiation protection. In this embodiment, the proton therapy system 1 has a proton extraction capability in the range of 70-230 megaelectron volts (MeV) and a maximum flow intensity of 2nA. When calculating, the proton therapy system 1 is analyzed according to the maximum flow intensity, and the equivalent dose (unit is mSv) for comparative analysis to obtain the radiation dose distribution diagrams shown in Figures 3-4.

Figure 3 is the dose distribution diagram of the shield 3 in the middle cross section. The lower part of Figure 3 is a graphical representation of the dose distribution value. Figure 3 is marked with three standard lines, from left to right are 0.1mSv, 1mSv and 5mSv, In the distribution diagram, correspondingly draw the connection diagram of the above standard lines. It can be seen that each standard line almost falls on the side wall of the shield 3, wherein the outermost curve is the dose line of 0.1mSv, The middle curve is the dose line of 1 mSv, and the innermost curve is the dose line of 5 mSv, which proves that the shielding body 3 can shield the standard of radiating to 0.1 mSv. That is, the shielding body 3 can meet not only the radiation dose limit standard for professional personnel and the public in the national standard, but also the radiation dose limit standard in this embodiment.

Fig. 4 is a dose distribution diagram on the middle longitudinal section of the shield 3, and the lower part of Fig. 4 is a graphical representation of the dose distribution values. There are three standard lines marked on Fig. 4, from left to right are 0.1mSv, 1mSv and 5mSv, In the distribution diagram, correspondingly draw the above standard wiring diagram. It can be seen that each standard line almost falls on the side wall of the shield 3, wherein the outermost curve is the dose line of 0.1mSv, the middle The curve is a dose line of 1 mSv, and the innermost curve is a dose line of 5 mSv, which proves that the shielding body 3 can shield the standard of radiating to 0.1 mSv. That is, the shielding body 3 can meet not only the radiation dose limit standard for professional personnel and the public in the national standard, but also the radiation dose limit standard in this embodiment.

In this embodiment, each wall thickness of the shielding body 3 is designed and selected according to the minimum value. In specific implementation, it can be thickened according to the level of the cost budget and actual needs. This embodiment is limited to providing a proton therapy system. 1 The lower limit of the wall thickness for which the maximum flow intensity is designed.

Example Three

This embodiment is to provide a shield body 3 ', which has basically the same structure as the shield body 3 in the second embodiment, but differs from the shield body 3 in the second embodiment in that the shield body 3' uses a concrete layer 4 and iron The composite shielding wall formed by the material layer 5 constructs the cavity structure.

In the case of a composite shielding wall, the height and volume of each chamber are still designed according to the structural size of each part of the proton therapy system 1. Since iron material is a good shielding material, the composite shielding wall covered with iron material The radiation resistance is stronger, the combination of concrete and iron materials can reduce the thickness of the shielding layer, so the lower limit of the wall thickness of each chamber will change, but the lower limit is still based on the radiation distribution of the proton therapy system 1 Make conformable settings.

In this embodiment, the composite shielding wall is formed by coating the inner wall of the concrete layer 4 with the iron material layer 5, and according to the radiation dose distribution, not all the concrete layers 4 are covered with the iron material layer 5, only during radiation The iron material layer 5 is coated in the area with a large dose. It should be noted that the wall thickness of the shielding body 3 'mentioned below refers to the overall thickness of the shielding wall unless otherwise specified, that is, if it is only the concrete layer 4, the wall thickness is the thickness of the concrete layer 4; If it is a composite shield wall, the wall thickness is the overall thickness of the concrete layer 4 and the iron material layer 5, and there are corresponding special instructions for the thickness design of the iron material layer.

As shown in FIG. 5, the thickness of the upper and lower walls of the synchrotron chamber 31 'is set to 2m, and the thickness of the left wall of the synchrotron chamber 31' is set to 2m, wherein the lower part of the left wall is covered with a layer of iron material 5, iron material Layer 5 has a thickness of 30 cm. The iron material layer 5 replaces the 1 m thick concrete layer 4 added here, but the same shielding effect can be achieved, so that the left wall of the synchrotron chamber 31 ′ is 2 m. The lower wall of the synchrotron chamber 31 'is covered with a rectangular iron material layer 5 having a length of 700 cm, a width of 600 cm and a thickness of 60 cm.

The thickness of the upper and lower walls of the upper rotating rack chamber 321 'are set to 2m, and the thickness of the right wall of the upper rotating rack chamber is set to 2m, which is set to isolate the upper rotating rack chamber 321' and the labyrinth chamber 34 '; The side wall of the upper wall of the rotating frame room 321 'is covered with a layer of iron material 5 of 100 cm, which can replace the 1 m thick concrete layer 4 added here; the right wall of the upper rotating frame room 321' is close to the rear side The part is covered with a 50 cm layer of iron material 5 to replace the 1 m thick concrete layer 4 originally designed here.

The upper wall of the lower rotating frame chamber 322 'is the lower wall of the upper rotating frame chamber 321', the side wall thickness of the lower rotating frame chamber 322 'is 2m, and the wall thickness of the lower wall is 2m. The side walls of the lower rotating frame chamber 322 'are covered with a 50cm thick iron material layer 5, and the right side portion of the lower wall of the lower rotating frame chamber 322' is covered with a 60cm thick iron material layer 5, so set The lower wall of the lower rotating frame chamber 322 'can be effectively reduced by 1 m in thickness.

The thicknesses of the front wall and the rear wall of the entire synchrotron chamber 31 'and the upper rotating frame chamber 321' are set to 2m, which is one-third lower than the setting of the wall thickness of 3m in the second embodiment, because The front wall and the rear wall of the synchrotron chamber 31 'and the upper rotating frame chamber 321' are covered with a layer 5 of iron material. In one embodiment, the iron material layer 5 is set to 50 cm on the rear wall of the synchrotron chamber 31 'and 20 cm on the front wall of the synchrotron chamber 31'; but the iron material layer 5 is behind the upper rotating frame chamber 321 ' The thickness of the wall is increased to 100cm, and it is set to 70cm on the front wall of the upper rotating gantry chamber 321 '. The main reason is that according to the standard dose line in Figure 3, on the front and rear walls of the upper rotating gantry chamber 321' The radiation dose is greater than the dose of the front wall and the rear wall of the synchrotron chamber 31 ', so the thickness of the iron material layer 5 of the upper rotating frame chamber 321' needs to be set thicker.

The thickness of the upper wall, the thickness of the lower wall, the thickness of the right wall and the rear wall of the labyrinth chamber 34 'are all set to 1m, and the thickness of the front wall is set to 2m.

In order to further enhance the radiation resistance of the upper rotating rack chamber 321 ', a layer of shielding wall is added to the outer wall of the right wall of the upper rotating rack chamber 321', and the shielding wall is located above the labyrinth chamber 34 'with a thickness of 0.5m.

The upper wall of the equipment room 35 'is the lower wall of the labyrinth room 34'. The thickness of the lower and right walls of the equipment room 35 'is 0.5m. The equipment room 35' and the lower rotating rack room 322 'pass through the lower rotating rack The right wall of chamber 322 'is isolated.

Since the radiation dose in the labyrinth room 34 'and the equipment room 35' is small, the iron material layer 5 is no longer provided for the equipment room 35 'and the labyrinth room 34' in this embodiment.

According to the second embodiment, for the specific wall thickness design of the shield 3 ′ in this embodiment, a Monte Carlo algorithm is used to simulate and analyze the radiation distribution of the shield 3 ′ to verify the shield 3 ′ of this embodiment. The design of the structure and thickness can meet the requirements of radiation protection. During the calculation, the maximum flow intensity of the proton therapy system is still used for analysis, and the radiation dose distribution diagram shown in FIGS. 6 to 7 is obtained.

Fig. 6 is the dose distribution diagram of the shield 3 'in the middle cross section. The lower part of Fig. 6 is a graphical representation of the dose distribution values. There are three standard lines marked on Fig. 6, from left to right are 0.1mSv, 1mSv and 5mSv , Correspondingly draw the above standard wiring diagram in the distribution diagram, you can see that each standard line still almost falls on the side wall of the shield 3 ', where the outermost curve is the dose of 0.1mSv Line, the middle curve is the dose line of 1mSv, and the innermost curve is the dose line of 5mSv, which proves that the shield 3 'can shield the standard of radiation to 0.1mSv, not to mention the standards of 1mSv and 5mSv. That is, the shielding body 3 'can not only meet the radiation dose limit standard for professional personnel and the public in the national standard, but also meet the radiation dose limit standard in this embodiment.

Fig. 7 is the dose distribution diagram of the shield 3 'in the middle longitudinal section. The lower part of Fig. 7 is a graph of the dose distribution values. There are three standard lines marked on Fig. 7, from left to right are 0.1mSv, 1mSv and 5mSv , Correspondingly draw the above standard wiring diagram in the distribution diagram. It can be seen that each standard line almost falls on the side wall of the shield 3 ′, where the outermost curve is the dose line of 0.1mSv The middle curve is the dose line of 1mSv, and the innermost curve is the dose line of 5mSv, which proves that the shield 3 'can shield the standard of radiating to 0.1mSv, not to mention the standards of 1mSv and 5mSv. That is, the shielding body 3 'can not only meet the radiation dose limit standard for professional personnel and the public in the national standard, but also meet the radiation dose limit standard in this embodiment.

It can be seen that the design of the composite shielding wall covered with the iron material layer 5 can reduce the wall thickness of the corresponding shielding body 3 'by at least one third, so that the wall thickness of the entire shielding body 3' is more uniform. Without reducing the shielding effect, the occupied space of the shielding body 3 'is reduced.

In this embodiment, each wall thickness of the shielding body 3 'and the thickness of the iron material layer 5 are designed according to the maximum flow strength of the proton therapy system. In specific implementation, it can be based on the cost budget and actual needs. For the thickening process, this embodiment is limited to providing a lower limit value.

Example 4

As mentioned in the first embodiment, the rotating frame chamber 32 and the synchrotron chamber 31 communicate with each other, and no shielding wall is provided. The purpose of this embodiment is to provide a verification method. No matter what shielding material is used to isolate the rotating gantry chamber 32 and the synchrotron chamber 31, for the target body 2, the radiation dose around the target body 2 will not Effectively reduce.

The simulation analysis of the radiation distribution of the shield 3 is performed according to the Monte Carlo algorithm. In one embodiment, the calculation is performed according to the maximum flow intensity of the proton therapy system 1, the effective dose (unit Gy) is used for comparative analysis, and the radiation dose near the scanning treatment head 15 and the target body 2 is focused on.

The radiation dose distribution diagram of the proton therapy system 1 shown in FIG. 8 shows from left to right that there is no shielding wall between the rotating gantry 32 room and synchrotron room 31, and a shielding wall with a 10 cm concrete layer 4 And the radiation dose distribution of the proton therapy system 1 in the case of a composite shielding wall composed of a 5 cm concrete layer 4 and a 2 cm iron material layer 5. As shown in FIG. 9, the scanning treatment head 15 emits a proton flow toward the target body 2, and in the direction perpendicular to the scanning treatment head 15 emission direction, three points at 15 cm, 50 cm, and 200 cm from the center of the target body 2 are selected (that is, For points A1, B1, C1), the dose value is extracted. The specific values are shown in Table 2:

Table 2 Radiation dose distribution near the target under different conditions (unit: Gy)

It can be obtained from the table data that there are no shielding walls, a shielding wall with a 10cm concrete layer, and a composite shielding wall composed of a 5cm concrete layer and a 2cm iron material layer 5 around the target 2 The radiation dose does not change much, so no matter what kind of shielding material is used, the radiation dose around the target body 2 cannot be effectively reduced, which provides support for the embodiment of a synchrotron chamber 31 and a rotating gantry chamber 32 arranged in an integrated cavity structure The structure design can optimize the structure of the shield body and make the miniaturization of the shield body a reality.

Claims

A shield body for a proton therapy system, wherein the shield body (3) is a multi-chamber structure constructed by a shield wall, and the shield body (3) includes a synchrotron chamber (31) and a rotating gantry chamber ( 32), the synchrotron chamber (31) and the rotating frame chamber (32) communicate with each other;

Wherein, the rotating rack chamber (32) includes an upper rotating rack chamber (321), a lower rotating rack chamber (322), and the upper rotating rack chamber (321) and the lower rotating rack chamber (322) between the frame slots (323), the upper rotating frame chamber (321) is located on the upper part of the lower rotating frame chamber (322), and the upper rotating frame chamber (321) is arranged to The synchrotron chambers (31) communicate with each other and form a chamber.
The shield body according to claim 1, further comprising a treatment room (33), and a partition wall is provided between the upper rotating gantry room (321) and the treatment room (33).
The shield body according to claim 2, further comprising a labyrinth chamber (34), the labyrinth chamber (34) is disposed on one side of the upper rotating gantry chamber (321), and is connected to the treatment chamber (33) Interconnected

The labyrinth chamber (34) is provided with a labyrinth entrance and a labyrinth exit, the labyrinth entrance is communicated with the outside world, and the labyrinth exit is communicated with the treatment room (33).
The shield body according to claim 3, further comprising an equipment room (35), the equipment room (34) and the lower rotating rack room (322) are in communication with each other.
The shield body according to claim 4, wherein the shield wall is a concrete layer (4) structure.
The shielding body according to claim 5, wherein the thickness of the concrete layer (4) ranges from 0.5m to 3.5m.
The shielding body according to claim 4, wherein the shielding wall is a composite shielding wall structure, the composite shielding wall includes a concrete layer (4) and an iron material layer (5) coated on the concrete layer (4) .
The shielding body according to claim 7, wherein the thickness of the concrete layer (4) ranges from 0.5m to 3m.
The shield according to claim 8, wherein the thickness of the iron material layer (5) ranges from 15 cm to 120 cm.
The shield body according to claim 9, wherein the thickness value of the iron material layer (5) of the rotating gantry chamber (32) is greater than the iron material layer (5) of the synchrotron chamber (31) ) Thickness value.