Method for assembling micron-sized pencil beam space segmentation radiotherapy collimator

Abstract

The invention discloses an assembly method of a micron-sized pencil beam space segmentation radiotherapy collimator, which comprises the following steps: S1, designing parameters and distribution of pencil beam MBRT beam spots, and determining the size, spacing and shape of microbeams; according to the design requirement, the tungsten sheet is machined through the laser micropore machining technology; s2, stacking the processed tungsten sheets together to form a main body structure of the MBRT collimator; s3, punching needles with the same size as the micropores are adopted to penetrate through the micropores, so that the stacked tungsten sheets are accurately aligned; s4, in order to press the stacked tungsten sheets, two square-shaped structural bodies are manufactured through the 3D printing technology, the four corners of each structural body are each provided with four positioning holes, the positioning holes correspond to the micropores in the four corners of the tungsten sheets, the tungsten sheets are pressed through the positioning holes, a sandwich structure is formed, and the positioning holes are fixed through punching needles; s5, four C-shaped structural bodies are manufactured through the 3D printing technology, the sandwich structure is clamped, it is ensured that the tungsten sheet is evenly stressed in all directions, and manufacturing of the pen-shaped MBRT collimator is completed.

Description

Technical Field

[0001] The invention belongs to the technical field of radiotherapy, and in particular relates to an assembling method of a micron-level pencil beam space-segmented radiotherapy collimator. Background Art

[0002] Spatially Fractionated Radiotherapy (SFRT) has gradually become an important direction in tumor radiotherapy research because of its potential to improve tumor control rate while reducing damage to surrounding normal tissues. Minibeam Radiation Therapy (MBRT) is an emerging form of SFRT. Its principle is to irradiate the tumor through an array of multiple tiny X-ray beams (microbeams), so that the irradiated area produces high-dose peaks and low-dose valleys. This dose distribution characteristic allows tumor cells to be sufficiently killed in the high-dose area, while the low-dose area causes relatively little damage to normal tissues, thus achieving a balance between tumor killing and normal tissue protection.

[0003] In MBRT, the geometric characteristics of the beam spot arrangement have a direct impact on the dose peak-to-valley ratio, beam output factor, and treatment effect. Pencil beam is a common MBRT beam spot design method, which controls the dose distribution by arranging multiple cylindrical beam spots in a specific geometric structure (such as a hexagonal array). Pencil beam MBRT is different from traditional strip beam MBRT, which usually uses long strip beam spot arrangements to achieve larger target coverage. However, since pencil beam MBRT has significant advantages in dose peak-to-valley ratio and output factor, it is one of the important research directions of MBRT beam spot design.

[0004] The existing pencil-beam MBRT technology shows certain application prospects in microbeam radiotherapy, but it still faces many technical challenges in practical applications.

[0005] First, the manufacturing cost of pencil-beam MBRT is high, and usually requires the use of high-precision equipment (micrometer level) and moderately thick materials (such as lead or tungsten) to ensure the uniformity of the beam spot and dose control. This high requirement for materials and equipment increases the production cost and limits its widespread clinical application. The current clinical pencil beam is currently at the centimeter level, called GRID technology.

[0006] In addition, the beam spot arrangement and spacing control of pencil-beam MBRT are relatively complex, and any slight error will affect the dose distribution, which in turn has an adverse effect on the peak-to-valley ratio and treatment effect. Therefore, the production and debugging process is not only time-consuming, but also requires a lot of resources, resulting in low overall efficiency. In terms of structural design, pencil-beam MBRT usually adopts a hexagonal array to ensure that the distance between each beam spot is uniform. However, this geometric arrangement has extremely high precision requirements during the processing process, and any slight deviation may cause beam spot overlap or uneven spacing, further increasing the complexity of the structure and the difficulty of manufacturing. The uniformity of the valley dose is difficult to ensure, which may lead to insufficient protection of normal tissue and affect the safety and effectiveness of treatment. Summary of the invention

[0007] The purpose of the present invention is to solve the above problems and provide an assembling method of a micron-level pencil beam spatial fractionation radiotherapy collimator for solving the problems of high processing difficulty, high cost and poor precision of the existing spatial fractionation radiotherapy pencil beam collimator.

[0008] In order to solve the above technical problems, the technical solution of the present invention is: an assembly method of a micron-level pencil beam spatially segmented radiotherapy collimator, comprising the following steps:

[0009] S1. Design the parameters and distribution of the pencil beam MBRT beam spot, determine the size, spacing and shape of the microbeam; according to the design requirements, use laser micro-hole processing technology to process the tungsten sheet;

[0010] S2, stacking the processed tungsten sheets together to form the main structure of the MBRT collimator;

[0011] S3. To ensure that the microholes are perfectly aligned, a punch of the same size as the microhole is used to penetrate the microholes to align the stacked tungsten sheets precisely.

[0012] S4. In order to compress the stacked tungsten sheets, two "mouth"-shaped structures are manufactured using 3D printing technology. Four positioning holes are provided at the four corners of the structure. The positioning holes correspond to the microholes at the four corners of the tungsten sheets. The tungsten sheets are compressed through the positioning holes to form a "sandwich" structure, and the positioning holes are fixed with a punch.

[0013] S5. Use 3D printing technology to manufacture four "C"-shaped structures, clamp them into a "sandwich" structure, ensure that the tungsten sheet is evenly stressed in all directions, and finally complete the production of the pen-type MBRT collimator.

[0014] Furthermore, the diameter of the micropores of the tungsten sheet in S1 is 200-1000 μm, the spacing between the pore walls is 200-1000 μm, the thickness of the tungsten sheet is 0.1 mm, and the parameters and distribution of the beam spot of each tungsten sheet are the same.

[0015] Furthermore, the stacking thickness of the tungsten sheets in S2 is adjustable.

[0016] Furthermore, the diameter of the punching needle in S3 is the same as the diameter of the microhole of the tungsten sheet, and several punching needles pass through the microhole.

[0017] Furthermore, the inner side size of the "mouth"-shaped structure in S4 is 25*25mm, the outer side size is 30*30mm, the thickness is 3mm, and the positioning hole diameter is 1mm.

[0018] Furthermore, when the pen-type MBRT collimator in S5 is used for radiotherapy testing, the distribution of radiotherapy rays is verified using EBT4 film, and a circular radiotherapy beam with a field diameter of 1.5 cm forms evenly distributed micropores after passing through the collimator.

[0019] Furthermore, the "C"-shaped structure in S5 is a concave rectangular parallelepiped.

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention provides a method for assembling a micron-level pencil beam spatially segmented radiotherapy collimator, which can provide a pencil beam MBRT assembly method with higher efficiency and higher precision, thereby improving the treatment effect and reducing normal tissue damage.

[0022] 2. The present invention improves the alignment of microholes. By using punching needles of the same size as the microholes and "mouth"-shaped and "C"-shaped structures, the microholes on the tungsten sheet can be accurately aligned during the stacking process, reducing the errors caused by the processing and assembly processes, thereby improving the consistency and uniformity of the beam spot.

[0023] 3. The present invention reduces production costs. By combining laser micro-hole processing technology with 3D printing technology, it not only improves manufacturing accuracy, but also reduces material waste and labor costs in the manufacturing process, thereby improving production efficiency.

[0024] 4. The present invention enhances structural stability. The selection of tungsten material and reasonable structural design make the final pencil-type MBRT collimator have better durability and stability, can maintain its performance in actual use, and extend the service life of the equipment.

[0025] 5. The present invention has improved adaptability. The flexibility of the assembly method enables it to be adjusted according to different tumor types, locations and individualized needs of patients, thus meeting the personalized treatment requirements in clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of a pencil beam collimator of a micron-level pencil beam space-segmented radiotherapy collimator according to the present invention;

[0027] Figure 2Schematic diagram of beam spot parameters and distribution of a single tungsten sheet in the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the stacked tungsten sheets in the present invention;

[0029] Figure 4 is a schematic diagram of the punch needle passing through the tungsten sheet in the present invention;

[0030] Figure 5 It is a structural schematic diagram of the "mouth"-shaped structure in the present invention;

[0031] Figure 6 It is a schematic structural diagram of the "C" type structure in the present invention;

[0032] Figure 7 It is a diagram showing the radiation beam irradiation effect in the present invention. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0034] like Figures 1 to 7 As shown, the present invention provides a method for assembling a micron-level pencil beam spatially segmented radiotherapy collimator, comprising the following steps:

[0035] S1. Design the parameters and distribution of the pencil beam MBRT beam spot, determine the size, spacing and shape of the microbeam; according to the design requirements, use laser micro-hole processing technology to process the tungsten sheet.

[0036] In step S1, the diameter of the micropores of the tungsten sheet is 200-1000 μm, the spacing between the pore walls is 200-1000 μm, the thickness of the tungsten sheet is 0.1 mm, and the parameters and distribution of the beam spot of each tungsten sheet are the same.

[0037] In this embodiment, the distribution of microholes follows the design rules of the pencil beam. Specifically, six holes are evenly arranged around the central hole, each with a diameter of 600 μm and a hole wall spacing of 600 μm. All holes are the same size and the spacing between holes is consistent. This symmetrical layout helps to achieve uniformity and accuracy of pencil beam irradiation. Through laser microhole processing technology, the microhole array is processed according to this design drawing to ensure the specific shape and distribution of the treatment beam spot and optimize the treatment effect of MBRT. The processing material is tungsten sheet, tungsten sheet 30*30*0.1mm, such as Figure 2 shown.

[0038] S2. Stack the processed tungsten sheets together to form the main structure of the MBRT collimator.

[0039] The thickness of the tungsten sheet stack in step S2 can be adjusted. There are 20 tungsten sheets in total. The 20 tungsten sheets are stacked to form the main structure of the MBRT collimator, with a size of 30*30*2mm. Figure 3 shown.

[0040] S3. To ensure that the micro-holes are perfectly aligned, a punch needle of the same size as the micro-hole is used to pass through the micro-hole to align the stacked tungsten sheets precisely.

[0041] In step S3, the diameter of the punch needle is the same as the diameter of the microhole of the tungsten sheet, which is 600 microns. Several punch needles are passed through the microholes. In this embodiment, in order to completely align the microholes, several punch needles with a diameter of 600 microns are used to pass through the microholes to align the stacked tungsten sheets. Figure 4 shown.

[0042] S4. In order to compress the stacked tungsten sheets, 3D printing technology is used to manufacture two "mouth"-shaped structures. Four positioning holes are provided at the four corners of the structure. The positioning holes correspond to the microholes at the four corners of the tungsten sheets. The tungsten sheets are pressed through the positioning holes to form a "sandwich" structure, and the positioning holes are fixed with a punch.

[0043] In step S4, the inner size of the "mouth"-shaped structure is 25*25mm, the outer size is 30*30mm, the thickness is 3mm, and the positioning hole diameter is 1mm. In this embodiment, in order to compress the stacked tungsten sheets on both sides, two "mouth"-shaped structures are printed using 3D printing technology. There are four positioning holes at the four corners of the structure, corresponding to the micropores at the four corners of the tungsten sheet; the "mouth"-shaped structure is pressed from both sides of the tungsten sheet to form a "sandwich" structure, and the four positioning holes are fixed with a punch, such as Figure 5 shown.

[0044] S5. Use 3D printing technology to manufacture four "C"-shaped structures, clamp them into a "sandwich" structure, ensure that the tungsten sheet is evenly stressed in all directions, and finally complete the production of the pencil-type MBRT collimator. Figure 6 shown.

[0045] When the pen-type MBRT collimator is used for radiotherapy testing in step S5, the distribution of radiotherapy rays is verified using EBT4 film, such as Figure 7 As shown. A circular radiotherapy beam with a radiation field diameter of 1.5 cm forms uniformly distributed micro-holes after passing through the collimator. In step S5, the "C"-shaped structure is a rectangular concave shape.

[0046] In the above steps, the structure can be produced by 3D printing.

[0047] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for assembling a micron-level pencil beam spatially segmented radiotherapy collimator, characterized in that: The following steps are involved: S1. Design the parameters and distribution of the pencil beam MBRT beam spot, determine the size, spacing and shape of the microbeam; according to the design requirements, use laser micro-hole processing technology to process the tungsten sheet; S2, stacking the processed tungsten sheets together to form the main structure of the MBRT collimator; S3. To ensure that the micro-holes are perfectly aligned, a punch of the same size as the micro-hole is used to penetrate the micro-holes to align the stacked tungsten sheets precisely; S4. In order to compress the stacked tungsten sheets, two "mouth"-shaped structures are manufactured using 3D printing technology. Four positioning holes are provided at the four corners of the structure. The positioning holes correspond to the microholes at the four corners of the tungsten sheets. The tungsten sheets are compressed through the positioning holes to form a "sandwich" structure, and the positioning holes are fixed with a punch. S5. Use 3D printing technology to manufacture four "C"-shaped structures, which are clamped into a "sandwich" structure to ensure that the tungsten sheet is evenly stressed in all directions, and finally complete the production of the pen-type MBRT collimator.

2. The method for assembling a micron-level pencil beam spatially divided radiotherapy collimator according to claim 1, characterized in that: The diameter of the micropores of the tungsten sheet in S1 is 200-1000 μm, the spacing between the pore walls is 200-1000 μm, the thickness of the tungsten sheet is 0.1 mm, and the parameters and distribution of the beam spot of each tungsten sheet are the same.

3. The method for assembling a micron-level pencil beam spatially divided radiotherapy collimator according to claim 1, characterized in that: The stacking thickness of the tungsten sheets in S2 is adjustable.

4. The method for assembling a micron-level pencil beam spatially divided radiotherapy collimator according to claim 1, characterized in that: The diameter of the punch needle in S3 is the same as the diameter of the microhole of the tungsten sheet, and several punch needles pass through the microhole.

5. The method for assembling a micron-level pencil beam spatially divided radiotherapy collimator according to claim 1, characterized in that: The "mouth"-shaped structure in the S4 has an inner size of 25*25mm, an outer size of 30*30mm, a thickness of 3mm, and a positioning hole diameter of 1mm.

6. The method for assembling a micron-level pencil beam spatially divided radiotherapy collimator according to claim 1, characterized in that: When the pen-type MBRT collimator in S5 is used for radiotherapy testing, EBT4 film is used to verify the distribution of radiotherapy rays. A circular radiotherapy beam with a field diameter of 1.5 cm forms evenly distributed micropores after passing through the collimator.

7. The method for assembling a micron-level pencil beam spatially divided radiotherapy collimator according to claim 1, characterized in that: The "C"-shaped structure in S5 is a concave rectangular parallelepiped.

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