Assembly method of a micron-level pencil beam spatially segmented radiotherapy collimator

Abstract

The present invention discloses an assembling method of a micron-level pencil beam spatially segmented radiotherapy collimator, comprising the following steps: S1, designing parameters and distribution of a pencil beam MBRT beam spot, and determining the size, spacing, and shape of the microbeam; according to design requirements, processing tungsten sheets using laser micro-hole processing technology; S2, stacking the processed tungsten sheets together to form the main structure of the MBRT collimator; S3, using a punching needle of the same size as the micro-hole to pass through the micro-hole to accurately align the stacked tungsten sheets; S4, in order to compress the stacked tungsten sheets, using 3D printing technology to manufacture two "mouth"-shaped structures, with four positioning holes respectively provided at the four corners of the structure, the positioning holes corresponding to the micro-holes at the four corners of the tungsten sheet, the tungsten sheet being compressed through the positioning holes to form a "sandwich" structure, and the positioning holes being fixed by the punching needle; S5, using 3D printing technology to manufacture four "C"-shaped structures, clamping the "sandwich" structure, ensuring that the tungsten sheet is uniformly stressed in all directions, and completing the production of the pencil-type MBRT collimator.

Description

Technical Field

[0001] The present 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 research area in tumor radiotherapy due to its potential to improve tumor control rates while reducing damage to surrounding normal tissue. Microbeam radiation therapy (MBRT), an emerging form of SFRT, works by irradiating the tumor with an array of multiple tiny X-ray beams (microbeams), resulting in high-dose peaks and low-dose valleys in the irradiated area. This dose distribution ensures that tumor cells are adequately killed in the high-dose areas, while causing relatively less damage to normal tissue in the low-dose areas, 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 spots to achieve larger target coverage. However, due to its significant advantages in dose peak-to-valley ratio and output factor, pencil beam MBRT 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 application.

[0005] First, pencil-beam MBRT is expensive to manufacture, typically requiring high-precision equipment (micrometer-level) and materials of moderate thickness (such as lead or tungsten) to ensure beam spot uniformity and dose control. These high material and equipment requirements drive up production costs, limiting its widespread clinical application. Currently, pencil beams in clinical use are centimeter-level, known as GRID technology.

[0006] In addition, the arrangement and spacing control of the beam spots of pencil-beam MBRT are relatively complex. Any slight error will affect the dose distribution, which in turn has an adverse effect on the peak-to-valley ratio and the 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 requires extremely high precision during the processing process. The slightest deviation may cause the beam spots to overlap or the spacing to be uneven, 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 the treatment. Summary of the Invention

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

[0008] To solve the above technical problems, the technical solution of the present invention is: a method for assembling a micron-level pencil beam spatially fractionated radiotherapy collimator, comprising the following steps:

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

[0010] S2. Stack 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 microholes is used to pass through the microholes to align the stacked tungsten sheets precisely.

[0012] S4. To compact the stacked tungsten sheets, two "mouth"-shaped structures were manufactured using 3D printing technology. Four positioning holes were set at the four corners of the structure. The positioning holes corresponded to the micro-holes at the four corners of the tungsten sheets. The tungsten sheets were compacted through the positioning holes to form a "sandwich" structure, and the positioning holes were 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 pencil-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 thickness of the tungsten sheet stack 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 of the "mouth"-shaped structure in S4 is 25*25mm, the outer side 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, 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.

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

[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 fractionated radiotherapy collimator, which can achieve a more efficient and precise pencil beam MBRT assembly method, thereby improving the treatment effect and reducing normal tissue damage.

[0022] 2. The present invention improves the alignment of micropores. By using punching needles of the same size as the micropores and "mouth" and "C"-shaped structures, the micropores on the tungsten sheet can be accurately aligned during the stacking process, reducing the errors caused by the processing and assembly process, 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, which 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, meeting the personalized treatment requirements in clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of a pencil beam collimator and an assembly method of a micron-level pencil beam spatially segmented radiotherapy collimator according to the present invention;

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

[0028] Figure 3 Schematic diagram of the structure of the stacked tungsten sheets in the present invention;

[0029] Figure 4 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 of the present invention;

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

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

[0033] The present invention will be further described below with reference to 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, and determine the size, spacing, and shape of the microbeams. Use laser micro-hole processing technology to process tungsten sheets according to design requirements.

[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 micropores follows the design rules of the pencil beam. Specifically, six holes are evenly arranged around the central hole, each with a diameter of 600μm and a hole-wall spacing of 600μm. 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 micropore processing technology, the micropore 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 sheets 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 microholes are perfectly aligned, a punch with the same size as the microhole is used to pass through the microhole 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 microhole. 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 in FIG. A circular radiotherapy beam with a 1.5 cm diameter field forms uniformly distributed micropores 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 it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection 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 spot, determine the size, spacing, and shape of the microbeams; and process the tungsten sheet using laser micro-hole machining technology according to the design requirements. The micropores in the tungsten sheet in S1 have a diameter of 200-1000 μm, a wall spacing of 200-1000 μm, and a thickness of 0.1 mm. The beam spot parameters and distribution of each tungsten sheet are identical; all pores are the same size, and the spacing between pores is consistent. Six pores are evenly arranged around the central hole, each with a diameter of 600 μm and a wall spacing of 600 μm. All pores are the same size, and the spacing between pores is consistent. S2. Stack the processed tungsten sheets together to form the main structure of the MBRT collimator; The stacking thickness of the tungsten sheets in S2 is adjustable. The processing material is tungsten sheets, 30*30*0.1mm, and 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. S3. To ensure that the microholes are perfectly aligned, a punch of the same size as the microholes is used to pass through the microholes to align the stacked tungsten sheets precisely. 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 are passed through the microhole; several punch needles with a diameter of 600 microns are used to pass through the microhole; S4. To compact the stacked tungsten sheets, two "mouth"-shaped structures were manufactured using 3D printing technology. Four positioning holes were set at the four corners of the structure. The positioning holes corresponded to the micro-holes at the four corners of the tungsten sheets. The tungsten sheets were compacted through the positioning holes to form a "sandwich" structure, and the positioning holes were fixed with a punch. The inner size of the "mouth" structure in S4 is 25*25mm, the outer size is 30*30mm, the thickness is 3mm, and the positioning hole diameter is 1mm; S5. Use 3D printing technology to manufacture four "C"-shaped structures and clamp them into a "sandwich" structure to ensure that the tungsten sheet is evenly stressed in all directions, finally completing the production of the pencil-type MBRT collimator; The "C"-shaped structure in S5 is a rectangular parallelepiped with an inward concave shape.

2. The method for assembling a micron-level pencil beam spatially fractionated 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 diameter of 1.5 cm forms evenly distributed micropores after passing through the collimator.

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