Tungsten alloy particle collimator for medical linear accelerator

Abstract

The invention provides a tungsten alloy particle collimator for a medical linear accelerator, is suitable for precise radiotherapy, and relates to the field of medical physics. The device consists of three parts: a glass container, a polypropylene shaping fence and tungsten alloy particles. The whole glass container is in a cuboid shape and is used for loading tungsten alloy particles and the polypropylene plastic fence. The shaping fence is made of a polypropylene material and can be quickly constructed into a desired geometrical shape under specific conditions. Each tungsten alloy particle is composed of 95% of tungsten, 3.5% of nickel and 1.5% of copper, and the geometrical shape of each tungsten alloy particle is a solid sphere with the diameter equal to 1 mm. A large number of tungsten alloy particles can be stacked into an expected geometric structure under the action of the shaping fence, and a channel is provided for X-rays. According to the device, the expected radiation field of the conformal target area can be rapidly constructed on the medical linear accelerator, and the device is suitable for precise radiotherapy.

Description

Technical field:

[0001] The invention relates to the field of medical physics, in particular to a tungsten alloy particle collimator for a medical linear accelerator. Background technology:

[0002] The multi-leaf collimator is a key device for radiotherapy, which is composed of multiple high-density tungsten alloy blades. Under the control of the computer system, the position of each blade can be adjusted independently, and it has the advantages of high precision and flexibility. Therefore, the multi-leaf collimator can accurately control the shape and intensity of the radiation beam, so as to achieve efficient killing of cancer cells while protecting healthy tissue as much as possible. However, when conforming to the shape of the tumor, the radiation field formed by the multi-leaf collimator has a jagged boundary, which is easy to increase the patient's additional dose. In response to the clinical demand for high-precision and high-efficiency radiotherapy, the present invention proposes a tungsten alloy particle collimator for medical linear accelerators. The device uses tungsten alloy particles and polypropylene shaping enclosures to quickly construct an X-ray channel of complex shape, providing the desired radiation field of the conformal target area for radiotherapy. Summary of the invention:

[0003] In order to form a desired radiation field of a conformal target area in radiotherapy, the present invention provides a tungsten alloy particle collimator for a medical linear accelerator. The collimator is composed of a glass container, a polypropylene shaping enclosure and tungsten alloy particles.

[0004] The geometric shape of the glass container is a cuboid, which is used to load tungsten alloy particles and polypropylene shaping enclosures. Its length and width must be much larger than the maximum projection width of the X-ray beam, and the height is 10 cm to achieve the expected radiation shielding effect. The material of the shaping enclosure is polypropylene, and its critical temperature for softening under thermal stress is about 150 degrees Celsius. After heating and shaping, polypropylene has high strength, good fatigue resistance and stable chemical properties, and is non-toxic and harmless, and can be used repeatedly. Under the computer control system, guided by the planned target volume contour, polypropylene is shaped into the desired shape to provide a channel for X-rays. A single tungsten alloy particle is composed of 95% tungsten, 3.5% nickel and 1.5% copper, with a diameter of 1mm, and its high density gives it excellent radiation shielding ability. Combined with the polypropylene shaping enclosure, a large number of small-volume tungsten alloy particles can be stacked into a complex geometric structure, that is, the space between the glass container and the polypropylene enclosure is filled with tungsten alloy particles, and the enclosure is kept hollow inside, so that the X-ray beam can only pass through a given channel to form the desired field of the conformal target area. Figure 2 The schematic diagram of the conventional multi-leaf collimator and the tungsten alloy particle collimator of the present invention in conforming to the planned target volume is shown. The results show that the device of the present invention can better conform to the target area and avoid X-ray leakage and under-irradiation as much as possible. Description of the drawings:

[0005] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention but do not constitute a limitation of the present invention.

[0006] Figure 1 Tungsten alloy particle collimator for medical linear accelerator.

[0007] Figure 2 Schematic diagram of the conformal target area of ​​the multi-leaf collimator and tungsten alloy particle collimator. Specific implementation method:

[0008] 1. According to the radiotherapy plan, the physicist uses a computer to fit the target volume contour and records the fitting function;

[0009] 2. Under the computer control system, combined with specific processing and molding technology and contour functions, polypropylene enclosures of specific shapes can be quickly constructed in glass containers;

[0010] 3. Inject a large amount of tungsten alloy particles into the space outside the polypropylene enclosure to a certain thickness so that it can effectively shield X-rays;

[0011] 4. The X-ray beam after primary collimation hits the tungsten alloy collimator and is reshaped again, so that the X-ray beam passing through the tungsten alloy particle collimator can form the desired radiation field in the target area;

[0012] 5. At a fixed angle, the tungsten alloy particle collimator used in medical linear accelerators can quickly construct multiple predetermined sub-fields. Through step-by-step irradiation, the desired dose distribution can be superimposed.

Claims

1. Tungsten alloy particle collimator for medical linear accelerator, Features: a. The device consists of three parts: glass container, polypropylene plastic enclosure and tungsten alloy particles; b. The geometric shape of the glass container is a cuboid, which is used to load tungsten alloy particles and polypropylene plastic enclosures. Its length and width must be much larger than the maximum projection width of the X-ray beam, and its height is 10 cm to achieve the expected radiation shielding effect; c. The material of the shaping enclosure is polypropylene. After heating and shaping, polypropylene has high strength, good fatigue resistance and stable chemical properties, is non-toxic and harmless, and can be used repeatedly. Under the computer control system, guided by the planned target volume contour, polypropylene can be shaped into the desired shape to provide a channel for X-rays; d. The tungsten alloy particles are composed of 95% tungsten, 3.5% nickel and 1.5% copper, with a diameter of 1mm. The high density makes them have excellent radiation shielding ability. Combined with the polypropylene shaping enclosure, a large number of small-volume tungsten alloy particles can be stacked into a complex geometric structure, that is, the space between the glass container and the polypropylene enclosure is filled with tungsten alloy particles, and the enclosure is kept hollow, so that the X-ray beam can only pass through a given channel to form the desired radiation field of the conformal target area.

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