A double-layer grating for radiotherapy with arc field drawing and its control method

Abstract

The present invention discloses a double-layer grating for radiotherapy with arc-drawing field and a method thereof. The double-layer grating for radiotherapy comprises: a rotating base connected to a linear accelerator, and having a base field window extending therethrough for outputting the therapeutic rays of the accelerator, wherein the rotating base comprises a rotatable rotating assembly; a first multileaf grating assembly mounted on the rotating assembly, wherein the first multileaf grating assembly can be slid back and forth along the length extension direction of the base field window; a second multileaf grating assembly mounted on the first multileaf grating assembly; the first multileaf grating assembly having a first field window extending therethrough, wherein a first grating blade group capable of conformal adjustment is arranged in the first field window; the second multileaf grating assembly having a second field window extending therethrough, wherein a second grating blade group capable of conformal adjustment is arranged in the second field window; the base field window, the first field window, and the second field window are interconnected.

Description

Technical Field

[0001] The present invention relates to the technical field of radiotherapy equipment, and in particular to a double-layer grating for radiotherapy with a field arc drawn and a control method thereof. Background Art

[0002] Dynamic Multileaf Collimator (DMLC, grating), also known as Multileaf Collimator, is a new type of radiotherapy equipment developed with the development of radiotherapy technology. It can meet the requirements of radiotherapy very well. Through the movement of the leaves, it forms an irradiation field that matches the projection shape of the target area, accurately irradiating the target area, improving the treatment effect of tumors and the quality of life of patients. It is suitable for various radiotherapy methods, such as dynamic intensity modulated radiotherapy, volumetric rotation intensity modulated radiotherapy, spiral tomography, stereotactic radiotherapy, etc. The grating has the characteristics of fast and convenient, high efficiency, large irradiation field, short irradiation time, compact structure, and wide range of applications. It has replaced the traditional conformal alloy block and become a key core equipment of radiotherapy, which is of great significance to improving the accuracy of radiotherapy.

[0003] Medical linear electron accelerators require conformal X-ray control. Current accelerators utilize multi-leaf collimators to adapt the X-ray shape to the tumor's shape, thereby better sparing normal tissue and allowing more radiation to reach the cancerous tissue. Generally speaking, multi-leaf collimators in this field often feature large field-of-view, leaf-pack designs, and sometimes multi-layered gratings. Existing grating designs share a common characteristic: while the field of view is large, there is no room for improvement in leaf speed. This is primarily due to the fact that the mainstream design of multi-leaf collimators, both domestically and internationally, uses a motor to directly drive the lead screw, which in turn drives the leaf movement. However, the current minimum size and maximum output power limits of these motors have been reached. Further increasing leaf speed within the current design is technically difficult to achieve effectively, and the primary technical challenge lies in developing motors with higher performance and smaller dimensions.

[0004] Furthermore, precision radiotherapy accelerators are based on conventional radiotherapy accelerators with the addition of gratings. Conventional radiotherapy accelerators typically consisted of upper and lower tungsten gates, creating a square field for coarse radiotherapy. Precision radiotherapy accelerators utilize different types of gratings, whose blades are aligned with the patient's tumor to shape the field. Consequently, conventional precision radiotherapy accelerators inherit the upper and lower tungsten gates of conventional radiotherapy accelerators, each containing two tungsten alloy shielding blocks, for a total of four tungsten alloy shielding blocks. This complicates the design and drive control of the secondary collimator, or upper and lower tungsten gates, in conventional precision radiotherapy accelerators. Four drive mechanisms are required to drive the four tungsten alloy shielding blocks, increasing both structural and control complexity. In practice, treatment also requires a certain level of precision for the upper and lower tungsten gates. Furthermore, the large space occupied by the upper and lower tungsten gates limits the diameter of the ring structure of conventional precision radiotherapy accelerators to within 100 cm, making it difficult to treat larger patients.

[0005] In view of this, the present invention patent is proposed. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a double-layer grating and method for radiotherapy with arc field drawing. Specifically, the following technical solutions are adopted:

[0007] A double-layer grating for radiotherapy with a drawn arc field, comprising:

[0008] A rotating base is connected to the linear accelerator and has a penetrating base field window therein for outputting the therapeutic radiation of the accelerator. The rotating base includes a rotatable rotating assembly;

[0009] A first multileaf collimator assembly is mounted on the rotating assembly, and the first multileaf collimator assembly can be reciprocally slidable along the length extension direction of the base field window;

[0010] a second multileaf collimator assembly, mounted on the first multileaf collimator assembly;

[0011] The first multi-leaf grating assembly has a first field window extending therethrough, and a first grating blade group capable of conformal adjustment is arranged in the first field window. The second multi-leaf grating assembly has a second field window extending therethrough, and a second grating blade group capable of conformal adjustment is arranged in the second field window. The base field window, the first field window, and the second field window are interconnected.

[0012] As an optional embodiment of the present invention, the rotating assembly includes a rotating block and a distal end fixing plate, the rotating base includes a proximal end fixing plate, the proximal end fixing plate is fixedly connected to the linear accelerator, one end of the rotating block is rotatably mounted on the proximal end fixing plate, and the distal end fixing plate is fixed to the other end of the rotating block; windows are respectively provided on the proximal end fixing plate, the rotating block and the distal end fixing plate, and the windows are interconnected to form the base field window.

[0013] As an optional embodiment of the present invention, the first multi-leaf grating assembly includes a first blade box and a first blade electrical control box, the base field window has a certain extension length, the first blade box is installed on the remote source end fixing plate, and can be slid back and forth along the extension length direction of the base field window; the first field window is opened on the first blade box, and the first grating blade group is arranged in the first field window, and performs conformal adjustment movement along the extension length direction perpendicular to the base field window, and the first blade electrical control box is arranged on both sides of the first blade box, respectively controlling the first grating blade groups on both sides to perform adaptive movement.

[0014] As an optional embodiment of the present invention, a double-layer grating for radiotherapy with field arc drawing of the present invention includes a sliding assembly, wherein the sliding assembly includes a sliding guide rail, a sliding member and a driving member, wherein the sliding guide rail is arranged on the distal end fixing plate and is arranged along the extension length direction of the base field window, the sliding member is slidably arranged on the sliding guide rail, the driving member drives the sliding member to slide back and forth on the sliding guide rail, and the first blade box is installed on the sliding member.

[0015] As an optional embodiment of the present invention, the sliding member has a screw sleeve, the driving member is a driving motor, the output shaft of the driving motor is connected to the driving screw, and the screw sleeve is sleeved on the driving screw to control the forward and reverse rotation of the output shaft of the driving motor. Through the threaded transmission of the driving screw and the screw sleeve, the sliding member is driven to slide back and forth along the sliding guide rail.

[0016] As an optional embodiment of the present invention, the second multi-leaf grating assembly includes a second blade box and a second blade electrical control box, the second blade box is fixed on the first blade box, the second field window is opened on the first blade box, the second grating blade group is arranged in the second field window, and performs conformal adjustment movement along a direction perpendicular to the conformal adjustment movement direction of the second grating blade group, and the second blade electrical control box is arranged on both sides of the second blade box, respectively controlling the second grating blade groups on both sides to perform adaptive movement.

[0017] As an optional embodiment of the present invention, the rotating block of the rotating base is a shielding rotating block with a shielding function, and the first blade box of the first multi-leaf grating assembly is a first blade shielding box with a shielding function.

[0018] The present invention also provides a control method for the radiotherapy double-layer grating, comprising:

[0019] By controlling the rotation of the rotating base and the sliding of the first multi-leaf collimator assembly, a uniform annular arcing field with a fixed curvature radius and a non-uniform eccentric arcing field with a variable curvature radius are formed;

[0020] At the same time, conformal adjustment is performed by controlling the first grating blade group and the second grating blade group to achieve all-round conformity to various types of heteromorphic tumor lesions.

[0021] As an optional embodiment of the present invention, in a control method of the present invention, controlling the rotation of the rotating base and the sliding of the first multileaf collimator assembly to form a uniform annular drawn arc field with a fixed curvature radius and a non-uniform eccentric drawn arc field with a variable curvature radius includes:

[0022] Controlling the rotating base to start rotating;

[0023] During the rotation of the rotating base, the first multi-leaf collimator assembly is controlled to perform a reciprocating sliding motion with a fixed position on the rotating base to form a uniform annular arc field with a fixed curvature radius;

[0024] During the rotation of the rotating base, the first multi-leaf collimator assembly is controlled to perform a sliding motion on the rotating base with a reciprocating position change, thereby forming a non-uniform eccentric arcing field with a changing curvature radius.

[0025] As an optional embodiment of the present invention, a control method of the present invention includes:

[0026] When the rotating base and the first multileaf collimator assembly are controlled to remain in a fixed state, a single-point radiation field having a radiation field size range of the second radiation field window is formed;

[0027] When the rotating base is controlled to remain in a fixed state and the first multi-leaf collimator assembly is controlled to slide back and forth on the rotating base, a field size range is formed, with the field band extending from the center to the outside.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a double-layer grating for radiotherapy with a drawn-field arc. By miniaturizing the first field window of a first multileaf grating assembly and the second field window of a second multileaf grating assembly, the design of the grating blade assembly within the field window and the design of the drive mechanism for the grating blade assembly are simplified. Furthermore, the first and second multileaf grating assemblies in the miniaturized field window can be rotationally scanned on a rotating base, forming an equivalent field within the entire area. Simultaneously, the grating blades in the first and second multileaf grating assemblies are controlled to meet the field conformal function during tumor treatment. Furthermore, the sliding of the first and second multileaf grating assemblies during the rotational scanning process can form a uniform annular drawn-field arc by fixing the rotational curvature radius of the first multileaf grating assembly on the slide rail. By varying the rotational curvature radius of the first multileaf grating assembly on the slide rail, a non-uniform eccentric drawn-field arc can be formed. This makes it more adaptable to the treatment of tumors with different distribution characteristics, providing greater flexibility and enhanced intensity modulation capabilities.

[0030] The present invention provides a double-layer grating for radiotherapy with a field arc, which adopts a miniaturized grating field and a field area rotation scanning method, making the multi-leaf grating more flexible in conformity speed than the traditional multi-leaf grating, thereby achieving all-round conformity to various types of irregular tumor lesions; the structure is greatly simplified, and the longitudinal space occupied by the treatment head is smaller, which can provide patients with a larger lateral space.

[0031] The double-layer grating for radiotherapy with arc-drawn field of view of the present invention realizes an integrated self-shielding design, greatly simplifies the driving mechanism of the shielding component, reduces the probability of damage and failure of the shielding component, enhances reliability, and at the same time has good structural compactness, further expanding the diameter range of the tube in the treatment area, allowing patients of various shapes to enter the inner tube of the accelerator for treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A partial exploded view of a double-layer grating for radiotherapy with a drawn arc beam according to an embodiment of the present invention;

[0033] Figure 2 Assembly of a double-layer grating for radiotherapy with arc-drawn field according to an embodiment of the present invention Figure 1 ;

[0034] Figure 3 Assembly of a double-layer grating for radiotherapy with arc-drawn field according to an embodiment of the present invention Figure 2 ;

[0035] Figure 4 An example of a single-point radiation field formed by a double-layer grating for radiation therapy with a field arc drawn according to an embodiment of the present invention;

[0036] Figure 5An example of a field zone formed by a double-layer grating for radiotherapy with field arc drawing according to an embodiment of the present invention;

[0037] Figure 6 An example of a full-area equivalent radiation field formed by a double-layer grating for radiation therapy with a field arc drawn according to an embodiment of the present invention;

[0038] Figure 7 An embodiment of the present invention provides an example of an annular arcing field and a non-uniform eccentric arcing field formed by a double-layer grating for radiotherapy with arcing field. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0040] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions therein may be combined with each other.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0043] In the description of the present invention, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the inventive product is typically placed when in use, or the orientations or positional relationships commonly understood by those skilled in the art. Such terms are intended solely to facilitate the description of the present invention and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" and the like are used solely for distinction and should not be construed as indicating or implying relative importance.

[0044] See also Figure 1-Figure 3 As shown, a double-layer grating for radiotherapy with a drawn-arc beam in this embodiment includes:

[0045] The rotating base 100 is connected to the linear accelerator and has a penetrating base field window 104 therein for outputting the therapeutic radiation of the accelerator. The rotating base 100 includes a rotatable rotating assembly.

[0046] A first multileaf collimator assembly 200 is mounted on the rotating assembly. The first multileaf collimator assembly 200 can be reciprocally slidable along the length extension direction of the base field window 104;

[0047] A second multileaf collimator assembly 300 is mounted on the first multileaf collimator assembly 200;

[0048] The first multileaf grating assembly 200 has a first field window 202 extending therethrough, and a first grating blade group 203 capable of conformal adjustment is arranged in the first field window 202. The second multileaf grating assembly 300 has a second field window 302 extending therethrough, and a second grating blade group 303 capable of conformal adjustment is arranged in the second field window 302. The base field window 104, the first field window 202, and the second field window 302 are interconnected.

[0049] This embodiment of a double-layer grating for radiotherapy with a drawn-field arc utilizes a miniaturized field window design, simplifying the design of the grating blade assembly within the field window and the design of the drive mechanism for the grating blade assembly. Furthermore, the first and second multileaf grating assemblies 200 and 300 of the miniaturized field window can be rotationally scanned on a rotating base 100, forming an equivalent field within the entire area. Furthermore, the control of the grating blades in the first and second multileaf grating assemblies 200 and 300 satisfies the field conformal function required during tumor treatment. In addition, the sliding of the first multileaf grating assembly 200 and the second multileaf grating assembly 300 during the rotary scanning process can form a uniform annular arcing radiation field by fixing the rotational curvature radius of the first multileaf grating assembly 200 on the slide rail; and a non-uniform eccentric arcing radiation field can be formed by changing the rotational curvature radius of the first multileaf grating assembly 200 on the slide rail; it is more suitable for the treatment of tumors with different distribution characteristics, with higher flexibility and stronger intensity modulation capability.

[0050] Therefore, the double-layer grating for radiotherapy with arc-drawn field in this embodiment adopts a miniaturized grating field and a rotational scanning method of the field area, which makes the conformal speed of the multi-leaf grating more flexible than the traditional multi-leaf grating, and realizes all-round conformal treatment of various types of special-shaped tumor lesions; the structure is greatly simplified, and the longitudinal space occupied by the treatment head is smaller, which can provide patients with a larger lateral space.

[0051] As an optional implementation manner of this embodiment, the rotating assembly described in this embodiment includes a rotating block 102 and a distal source end fixing plate 103, and the rotating base 100 includes a proximal source end fixing plate 101, and the proximal source end fixing plate 101 is fixedly connected to the linear accelerator. One end of the rotating block 102 is rotatably mounted on the proximal source end fixing plate 101, and the distal source end fixing plate 103 is fixed to the other end of the rotating block 102; windows are respectively opened on the proximal source end fixing plate 101, the rotating block 102 and the distal source end fixing plate 103, and the windows are interconnected to form the base field window 104.

[0052] The rotating base 100 of this embodiment is fixedly connected to the linear accelerator via a near-source fixing plate 101. The rotating block 102 is rotatably mounted on the near-source fixing plate 101, thereby simultaneously driving the distal-source fixing plate 103 and the first and second multileaf collimator assemblies 200 and 300 disposed thereon to rotate. While the specific implementation of the rotation of the rotating block 102 is not illustrated in this embodiment, it will be understood by those skilled in the art that the rotating block 102 can be driven by a drive motor via a gear mechanism or by a drive motor via a pulley.

[0053] As an optional implementation of this embodiment, the first multi-leaf grating assembly 200 described in this embodiment includes a first blade box 201 and a first blade electrical control box 204, the base field window 104 has a certain extension length, the first blade box 201 is installed on the remote source end fixing plate 103, and can be slid back and forth along the extension length direction of the base field window 104; the first field window 202 is opened on the first blade box 201, and the first grating blade group 203 is arranged in the first field window 202, and performs conformal adjustment movement along the extension length direction perpendicular to the base field window 104, and the first blade electrical control box 204 is arranged on both sides of the first blade box 201, respectively controlling the first grating blade groups 203 on both sides to perform adaptive movement.

[0054] In order to realize that the first multi-leaf grating assembly 200 can be slidably set on the distal end fixed plate 103, as an optional implementation method of this embodiment, a double-layer grating for radiotherapy with field arc drawing in this embodiment includes a sliding assembly, and the sliding assembly includes a sliding guide rail 403, a sliding member 404 and a driving member 401. The sliding guide rail 403 is set on the distal end fixed plate 103 and is arranged along the extension length direction of the base field window 104. The sliding member 404 is slidably set on the sliding guide rail 403. The driving member 401 drives the sliding member 404 to slide back and forth on the sliding guide rail 403. The first blade box 201 is installed on the sliding member 404.

[0055] In order to enable the driving member 401 to drive the sliding member 404 to slide back and forth on the sliding guide rail 403, as an optional implementation scheme of this embodiment, the sliding member 404 described in this embodiment has a screw sleeve 405, and the driving member 401 is a driving motor. The output shaft of the driving motor is connected to the driving screw 402, and the screw sleeve 405 is sleeved on the driving screw 402 to control the forward and reverse rotation of the output shaft of the driving motor. Through the threaded transmission of the driving screw 402 and the screw sleeve 405, the sliding member 404 is driven to slide back and forth along the sliding guide rail 403.

[0056] As an optional implementation of this embodiment, the second multi-leaf grating assembly 300 includes a second blade box 301 and a second blade electrical control box 304, the second blade box 301 is fixed on the first blade box 201, the second field window 302 is opened on the first blade box 301, the second grating blade group 303 is arranged in the second field window 302, and performs conformal adjustment movement along a direction perpendicular to the conformal adjustment movement direction of the second grating blade group 200, and the second blade electrical control box 304 is arranged on both sides of the second blade box 301, respectively controlling the second grating blade groups 303 on both sides to perform adaptive movement.

[0057] In this embodiment, the first multileaf grating assembly 200 and the second multileaf grating assembly 300 are stacked up and down, and the first field window 202 and the second field window 302 are interconnected. By controlling the first grating blade group 203 of the first multileaf grating assembly 200 and the second grating blade group 303 of the second multileaf grating assembly 300, the final irradiation field is formed by superposition. The double-layer stacking design can simplify the structural design of the single-layer multileaf grating, and the grating blade group and the electrical control box mechanism are further simplified, and the overall structure is simpler.

[0058] To further illustrate, the first field window 202 and the second field window 302 are set to 10 cm×10 cm. Therefore, compared with the traditional 40 cm×40 cm grating blade window, the size and mass of the grating blades in this embodiment are reduced by half. Under the condition of unchanged driving capacity, the speed is greatly improved from 40 mm / s to more than 80-100 mm / s.

[0059] At the same time, the fixed radiation field, fixed blade width and double-layer structure adopted in this embodiment ensure that the conformal resolution is equally high in any radiation field area.

[0060] In this embodiment, a double-layer grating for radiotherapy with a beam arc is used. The first and second multileaf grating assemblies 200 and 300 utilize a small number of grating blades, correspondingly requiring only a few dozen blade drive mechanisms. Compared to conventional large gratings with over 200 blades, this reduced number of drive mechanisms significantly improves operational reliability. Furthermore, conventional gratings require the drivers of two additional blade packages to achieve a large beam field. However, this embodiment, due to its miniaturized beam window, eliminates the need for additional blade drivers, further reducing structural design complexity and improving operational reliability.

[0061] As an optional implementation of this embodiment, the rotating block 102 of the rotating base 100 described in this embodiment is a shielding rotating block, and the first blade housing 202 of the first multileaf grating assembly 200 is a shielding first blade shielding housing. Therefore, the double-layer grating for field-drawn radiotherapy in this embodiment achieves an integrated self-shielding design, greatly simplifying the drive mechanism of the shielding components, reducing the probability of shielding component damage and failure, and enhancing reliability. It also maintains a compact structure and further expands the range of cylinder diameters within the treatment area, allowing patients of all shapes and sizes to enter the accelerator's inner cylinder for treatment.

[0062] This embodiment also provides a control method using the radiotherapy double-layer grating, including:

[0063] By controlling the rotation of the rotating base and the sliding of the first multi-leaf collimator assembly, a uniform annular arcing field with a fixed curvature radius and a non-uniform eccentric arcing field with a variable curvature radius are formed;

[0064] At the same time, conformal adjustment is performed by controlling the first grating blade group and the second grating blade group to achieve all-round conformity to various types of heteromorphic tumor lesions.

[0065] Furthermore, in a control method described in this embodiment, controlling the rotation of the rotating base and the sliding of the first multileaf collimator assembly to form a uniform annular drawn arc field with a fixed curvature radius and a non-uniform eccentric drawn arc field with a variable curvature radius includes:

[0066] Controlling the rotating base to start rotating;

[0067] During the rotation of the rotating base, the first multi-leaf collimator assembly is controlled to perform a reciprocating sliding motion on the rotating base to form a uniform annular arc field with a fixed curvature radius (such as Figure 7 Example of circular arcing field on the left side of the center);

[0068] During the rotation of the rotating base, the first multi-leaf collimator assembly is controlled to perform a sliding motion on the rotating base to change its position back and forth, thereby forming a non-uniform eccentric arcing field with a varying curvature radius (such as Figure 7 (Non-uniform eccentric arcing field in the middle right example).

[0069] As an optional implementation manner of this embodiment, a control method of this embodiment includes:

[0070] When the rotating base and the first multileaf grating assembly are controlled to remain in a fixed state, a single-point field with a field size range of the second field window is formed (see Figure 4 single point field as shown);

[0071] When the rotating base is controlled to remain in a fixed state and the first multi-leaf grating assembly is controlled to slide back and forth on the rotating base, a field size range is formed in which a field band extends from the center to the outside (see Figure 5 field strips as shown).

[0072] When the rotating base is controlled to rotate, and the first multi-leaf collimator assembly is controlled to slide back and forth from the innermost side to the outermost side along the base window during the rotation of the rotating base, an equivalent radiation field can be formed in the entire area (see Figure 6 Full area equivalent field shown as an example).

[0073] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A double-layer grating for radiotherapy with a drawn arc field, characterized in that: include: A rotating base is connected to the linear accelerator and has a penetrating base field window therein for outputting the therapeutic radiation of the accelerator. The rotating base includes a rotatable rotating assembly; A first multileaf collimator assembly is mounted on the rotating assembly, and the first multileaf collimator assembly can be reciprocally slidable along the length extension direction of the base field window; a second multileaf collimator assembly, mounted on the first multileaf collimator assembly; The first multileaf grating assembly has a first field window extending therethrough, and a first grating blade group capable of conformal adjustment is disposed in the first field window. The second multileaf grating assembly has a second field window extending therethrough, and a second grating blade group capable of conformal adjustment is disposed in the second field window. The base field window, the first field window, and the second field window are interconnected. The rotating assembly includes a rotating block and a distal end fixing plate, the rotating base includes a proximal end fixing plate, the proximal end fixing plate is fixedly connected to the linear accelerator, one end of the rotating block is rotatably mounted on the proximal end fixing plate, and the distal end fixing plate is fixed to the other end of the rotating block; The proximal source end fixing plate, the rotating block and the distal source end fixing plate are respectively provided with windows, and the windows are interconnected to form the base field window; The first multi-leaf grating assembly includes a first blade box and a first blade electric control box. The base field window has a certain extension length. The first blade box is mounted on the remote source end fixing plate and can be reciprocated and slidably arranged along the extension length direction of the base field window. The first field window is opened on the first blade box. The first grating blade group is arranged in the first field window and performs conformal adjustment movement along the extension length direction perpendicular to the base field window. The first blade electric control boxes are arranged on both sides of the first blade box to respectively control the first grating blade groups on both sides to perform adaptive movement. The double-layer grating for radiotherapy with field arc drawing includes a sliding assembly, which includes a sliding guide rail, a sliding member and a driving member. The sliding guide rail is arranged on the distal end fixing plate and is arranged along the extension length direction of the base field window. The sliding member is slidably arranged on the sliding guide rail, and the driving member drives the sliding member to slide back and forth on the sliding guide rail. The first blade box is installed on the sliding member.

2. The double-layer grating for radiotherapy with drawn arc according to claim 1, characterized in that: The sliding member has a screw sleeve, the driving member is a driving motor, the output shaft of the driving motor is connected to the driving screw, and the screw sleeve is sleeved on the driving screw to control the forward and reverse rotation of the output shaft of the driving motor. Through the threaded transmission of the driving screw and the screw sleeve, the driving sliding member slides back and forth along the sliding guide rail.

3. The double-layer grating for radiotherapy with drawn arc according to claim 1, characterized in that: The second multi-leaf grating assembly includes a second blade box and a second blade electrical control box. The second blade box is fixed on the first blade box. The second field window is opened on the first blade box. The second grating blade group is arranged in the second field window and performs conformal adjustment movement perpendicular to the conformal adjustment movement direction of the second grating blade group. The second blade electrical control box is arranged on both sides of the second blade box to respectively control the second grating blade groups on both sides to perform adaptive movement.

4. The double-layer grating for radiotherapy with drawn arc according to claim 3, characterized in that: The rotating block of the rotating base is a shielding rotating block with a shielding function, and the first blade box of the first multi-leaf grating assembly is a first blade shielding box with a shielding function.

5. A control method for a double-layer grating for radiotherapy according to any one of claims 1 to 4, characterized in that: include: By controlling the rotation of the rotating base and the sliding of the first multi-leaf collimator assembly, a uniform annular arcing field with a fixed curvature radius and a non-uniform eccentric arcing field with a variable curvature radius are formed; At the same time, conformal adjustment is performed by controlling the first grating blade group and the second grating blade group to achieve all-round conformity to various types of heteromorphic tumor lesions.

6. A control method according to claim 5, characterized in that: The step of controlling the rotation of the rotating base and the sliding of the first multi-leaf collimator assembly to form a uniform annular arcing field with a fixed curvature radius and a non-uniform eccentric arcing field with a variable curvature radius includes: Controlling the rotating base to start rotating; During the rotation of the rotating base, the first multi-leaf collimator assembly is controlled to perform a reciprocating sliding motion with a fixed position on the rotating base to form a uniform annular arc field with a fixed curvature radius; During the rotation of the rotating base, the first multi-leaf collimator assembly is controlled to perform a sliding motion on the rotating base with a reciprocating position change, thereby forming a non-uniform eccentric arcing field with a changing curvature radius.

7. A control method according to claim 5, characterized in that: include: When the rotating base and the first multileaf collimator assembly are controlled to remain in a fixed state, a single-point radiation field having a radiation field size range of the second radiation field window is formed; When the rotating base is controlled to remain in a fixed state and the first multi-leaf collimator assembly is controlled to slide back and forth on the rotating base, a field size range is formed, with the field band extending from the center to the outside.

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