Radiotherapy dose test method and system based on space body distributed multi-layer ionization chamber

Abstract

The invention discloses a radiation therapy dose inspection system and method based on a space body distributed multi-layer ionization chamber. The radiation therapy dose inspection system comprises a cylindrical die body with a space body distributed ionization chamber matrix, a suspended supporting base capable of being adjusted to be horizontal, other functional plug-ins and matched software. According to the system and the method, a novel high-pressure transmission mode is adopted, a cylinder distributed air leakage type ionization chamber with higher spatial resolution is used for small radiation field measurement in radiotherapy, dose body distribution of radiotherapy radiation at various angles and depths can be collected and measured at a time without rotating a die body and angle correction, and the measurement accuracy is improved. And finally, the spatial distribution of the radiation dose in the cylindrical die body is obtained through software calculation, and high-precision measurement is realized.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy dose testing technology, and in particular to a radiotherapy dose testing system and method based on a space-distributed multilayer ionization chamber. Background Technology

[0002] Most existing probes for acquiring and measuring radiation dose in radiotherapy are planar, capable of acquiring doses only on a single plane. For multi-angle radiotherapy doses, automatic or manual rotation is generally used for acquisition, or only a few specific planar doses are acquired. A few probes with volumetric distribution typically have distributions only on the surface or in two layers, and are often large in size or widely spaced, making them suitable only for large radiotherapy fields. Cylindrical ionization chamber matrices generally have a bottom support structure, requiring dosimetric corrections to this structure during use. Therefore, this application aims to provide a radiotherapy dose verification system and method based on a spatially distributed multilayer ionization chamber that overcomes the above-mentioned shortcomings. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a radiotherapy dose testing system and method based on a space-distributed multilayer ionization chamber.

[0004] The objective of this invention is achieved through the following technical solution: A radiotherapy dose verification system based on a spatially distributed multilayer ionization chamber, comprising a phantom with an ionization chamber matrix phantom and a supporting base. The ionization chamber matrix phantom includes: an ionization chamber matrix assembly, which adopts a stacked structure of double-layer ionization chambers, forming a cylindrical distributed ionization chamber matrix in a stacked manner of multiple sets of double-layer ionization chambers, wherein adjacent sets of ionization chambers are high-voltage connected in a spatially staggered manner; a solid water phantom support for supporting the ionization chamber matrix assembly; and a processing circuit disposed on the solid water phantom support and electrically connected to the ionization chamber matrix assembly.

[0005] Preferably, each ionization chamber includes a flexible high-voltage plate, an outer ring acrylic plate, a collecting plate, and an inner ring acrylic plate. The flexible high-voltage plate is composed of a first plate and a second plate connected to each other. The ionization chamber is constructed by stacking the first plate, the outer ring acrylic plate, the collecting plate, the inner ring acrylic plate, and the second plate in sequence.

[0006] Preferably, both the first plate and the second plate are provided with a plurality of high-voltage transmission windows and a plurality of ionization chamber high-voltage windows. The outer ring acrylic plate and the inner ring acrylic plate are provided with a plurality of openings. The front and back of the collecting plate are provided with a plurality of collection windows. In the stacked state, the ionization chamber high-voltage windows, the openings and the collection windows are aligned with each other.

[0007] Preferably, in the stacked state, the high-voltage ionization chamber windows on the first plate and the high-voltage ionization chamber windows on the second plate are staggered. The high-voltage ionization chamber windows of the first plate, the openings on the outer acrylic plate, and the collection windows on the reverse side of the collection plate are aligned with each other. The high-voltage ionization chamber windows of the second plate, the openings on the inner acrylic plate, and the collection windows on the front side of the collection plate are aligned with each other.

[0008] Preferably, the high-voltage windows of several ionization chambers are arranged in a ring. In the state where several groups of ionization chambers are stacked on top of each other, the high-voltage transmission windows of the previous group of ionization chambers are aligned with the high-voltage transmission windows of the next group of ionization chambers. After the last group of ionization chambers is stacked, a high-voltage connection board is used to connect the ionization chamber matrix to the high-voltage module of the processing circuit. The acquisition board of each group of ionization chambers is electrically connected to the acquisition and analysis module of the processing circuit.

[0009] Preferably, the first plate, the second plate, the outer acrylic plate, the inner acrylic plate, and the collecting plate are all provided with mutually aligned fixing holes, and fastening bolts can be nested in the fixing holes.

[0010] Preferably, the mold body and the support base are connected by a support plate, the support plate is provided with a handle, and the support base is provided with a horizontal adjustment component and a counterweight assembly, wherein the counterweight assembly can slide along a set direction.

[0011] Preferably, the counterweight assembly includes a counterweight slide plate and a counterweight block disposed on the counterweight slide plate. The counterweight slide plate is provided with a plurality of locking slots, and the support base is provided with an elastic bullseye ball.

[0012] Preferably, the ionization chamber matrix assembly is formed by stacking 1020 ionization chambers on top of each other, with a length of 79.4 mm and a diameter of 104 mm.

[0013] A radiotherapy dose verification method based on a spatially distributed multilayer ionization chamber employs a novel high-voltage transmission method. This method utilizes a cylindrical distributed ionization chamber with higher spatial resolution for small radiation field measurements in radiotherapy. Without requiring phantom rotation or angle correction, it can simultaneously acquire and measure the dose distribution of radiotherapy radiation at various angles and depths. The novel high-voltage transmission method is implemented as follows: the ionization chamber matrix phantom is configured to include ionization chamber matrix components, employing a stacked structure of double-layer ionization chambers. A cylindrical distributed ionization chamber matrix is ​​formed by stacking multiple double-layer ionization chambers, with adjacent ionization chambers connected by high voltage in a spatially staggered manner.

[0014] This invention offers the following advantages: the various groups of double-layer ionization chambers are connected by compression contact through high-voltage windows with through-holes, rather than through conductive plastic rods or thin copper wires. This design reduces the impact of high-voltage wires on the ionization chamber matrix, lowers assembly difficulty, and improves the yield rate of the finished product. In cases where insufficient compression might lead to inadequate contact, the high-voltage flexible plate also has multiple high-voltage openings with through-holes, greatly reducing the possibility of high-voltage circuit breakage in such situations. The degree of compression between the ionization chambers can also be adjusted manually by controlling the tightness of the fixing bolts. This design can be used for all volumetric vented flat-plate ionization chamber matrices and can be adapted for various applications by adjusting the size and spacing of the ionization chambers. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the radiotherapy dose testing system of the present invention; Figure 2 This is a schematic diagram of the ionization chamber matrix assembly; Figure 3 This is a schematic diagram of the flexible high-voltage plate. Figure 4 This is a schematic diagram illustrating the installation method of the high-pressure transfer window; Figure 5 This is a schematic diagram of the overall structure of the ionization chamber matrix model; Figure 6 This is a diagram illustrating how the handle is set up. Figure 7 This is a schematic diagram of the counterweight assembly. Figure 8 This is a schematic diagram of the horizontal adjustment component; In the diagram, 1-mold body, 2-ionization chamber matrix mold body, 3-support base, 2a-ionization chamber matrix assembly, 2b-solid water model support, 2c-processing circuit, 4-flexible high-pressure plate, 5-outer ring acrylic plate, 6-collection plate, 7-inner ring acrylic plate, 4a-first plate body, 4b-second plate body, 8-high-pressure transfer window, 9-ionization chamber high-pressure window, 10-high-pressure connection plate, 11-fixing hole, 12-support plate, 13-handle, 14-level adjustment component, 15-counterweight assembly, 15a-counterweight slide plate, 15b-counterweight block, 16-slot, 17-elastic bullseye ball. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description: This invention provides a method and system for acquiring and measuring the radiation dose distribution in radiotherapy using a multi-layered ionization chamber based on spatial volume distribution. The system includes a cylindrical phantom with a spatially distributed ionization chamber matrix, an adjustable horizontal suspended support base, other functional modules, and supporting software. The system employs a novel high-voltage transmission method, utilizing a cylindrically distributed, vented ionization chamber with higher spatial resolution for small radiation field measurements in radiotherapy. Without requiring phantom rotation or angle correction, it can simultaneously acquire and measure the dose distribution of radiotherapy radiation at various angles and depths. Finally, the spatial distribution of radiation dose within the cylindrical phantom is calculated by the software, achieving high-precision measurement.

[0017] like Figures 1 to 8As shown, this application provides a radiotherapy dose verification system based on a spatially distributed multilayer ionization chamber, including a phantom 1 with an ionization chamber matrix phantom 2 and a support base 3. The ionization chamber matrix phantom 2 includes: an ionization chamber matrix assembly 2a, which adopts a stacked structure of double-layer ionization chambers, forming a cylindrical distributed ionization chamber matrix in a stacked manner of double layers and multiple sets, wherein adjacent sets of ionization chambers are high-voltage connected in a spatially staggered manner; a solid water phantom support 2b, used to support the ionization chamber matrix assembly 2a; and a processing circuit 2c, disposed on the solid water phantom support 2b and electrically connected to the ionization chamber matrix assembly 2a. Each set of ionization chambers includes a flexible high-voltage plate 4, an outer ring acrylic plate 5, a collecting plate 6, and an inner ring acrylic plate 7. The flexible high-voltage plate 4 is composed of a first plate 4a and a second plate 4b connected to each other. The ionization chambers are constructed by stacking the first plate 4a, the outer ring acrylic plate 5, the collecting plate 6, the inner ring acrylic plate 7, and the second plate 4b in sequence. Both the first plate 4a and the second plate 4b are provided with a plurality of high-voltage transmission windows 8 and a plurality of ionization chamber high-voltage windows 9. The outer ring acrylic plate 5 and the inner ring acrylic plate 7 are provided with a plurality of openings. The front and back surfaces of the collecting plate 6 are provided with a plurality of collection windows. In the stacked state, the ionization chamber high-voltage windows 9, the openings, and the collection windows are aligned one-to-one. In the stacked state, the ionization chamber high-voltage windows 9 on the first plate 4a and the ionization chamber high-voltage windows 9 on the second plate 4b are staggered. Specifically, the ionization chamber high-voltage windows 9 of the first plate 4a, the openings on the outer ring acrylic plate 5, and the collection windows on the back surface of the collecting plate 6 are aligned with each other; the ionization chamber high-voltage windows 9 of the second plate 4b, the openings on the inner ring acrylic plate 7, and the collection windows on the front surface of the collecting plate 6 are aligned with each other. Several high-voltage windows 9 of the ionization chambers are arranged in a ring. When several groups of ionization chambers are stacked, the high-voltage transfer windows 8 of the previous group of ionization chambers are aligned with the high-voltage transfer windows 8 of the next group. After the last group of ionization chambers is stacked, a high-voltage connecting plate 10 connects the ionization chamber matrix to the high-voltage module of the processing circuit 2c. The acquisition board of each group of ionization chambers is electrically connected to the acquisition and analysis module of the processing circuit 2c. The first plate 4a, the second plate 4b, the outer acrylic plate 5, the inner acrylic plate 7, and the collection plate 6 are all provided with aligned fixing holes 11, which can be fitted with fastening bolts. The ionization chamber matrix assembly 2a is formed by stacking 1020 ionization chambers, with a length of 79.4 mm and a diameter of 104 mm. Specifically, as shown... Figure 5As shown, the core of this application is a cylindrical distributed ionization chamber matrix with high spatial resolution. The ionization chamber matrix component 2a, the solid water model support 2b, and the processing circuit 2c can all be encased in an ABS shell. The ionization chamber cavities are spatially staggered to avoid mutual interference and achieve full coverage along the circumference. The high-voltage connection method is innovative based on existing technology. When multiple sets of double-layer structures are stacked one after another, the high voltage of the previous set is connected to the high voltage of the next set, realizing the series connection of the high-voltage ionization chamber matrix. The ionization chamber matrix is ​​specially designed with double-sided high-voltage flexible plates. By bending, the inner and outer ring acrylic plates and the collection plate are clamped. The copper-plated positions of the high-voltage windows of the inward-facing ionization chambers correspond one-to-one with the opening positions of the inner or outer ring acrylic plates and the collection windows on the collection plate, as shown by the dashed lines in Figure 3. The outward-facing end face has high-voltage windows with a central inner hole and copper plating on the outer hole. The positions of the high-voltage windows on the front and rear end faces are mirror-symmetrical and correspond to each other after bending, as shown by the solid lines in Figure 3. When assembling a single double-layer ionization chamber, the high-voltage windows (high-voltage electrodes of the ionization chamber) of the high-voltage flexible plate without openings face each other, while the high-voltage transfer windows with openings face forward and backward, clamping the inner and outer rings of acrylic and the double-sided acquisition plate inwards (as shown in Figure 2). The acquisition plate has copper-plated, staggered ionization chamber acquisition electrodes on both the front and back, their positions corresponding to the holes on the inner and outer rings of acrylic and the high-voltage electrodes of the high-voltage flexible plate. After completing the single-unit assembly, when stacking multiple units, the through-hole high-voltage windows of the previous unit should face the through-hole high-voltage windows of the next unit (Figure 4), and the through holes of each unit should correspond one-to-one. Fixing bolts can be inserted to ensure tight contact between the multiple double-layer ionization chambers.

[0018] Preferably, the phantom 1 and the support base 3 are connected by a support plate 12. The support plate 12 is provided with a handle 13, and the support base 3 is provided with a horizontal adjustment component 14 and a counterweight assembly 15, wherein the counterweight assembly 15 can slide along a set direction. When using the ionization chamber matrix phantom, it must be inserted into the functional cavity of the spherical cylindrical phantom that is paired with the support frame. The structure of the support frame is as follows... Figure 1 As shown, the key spherical cylindrical phantom is a suspended homogeneous ABS structure with a cavity for inserting various functional components. This suspended phantom is fixed to a horizontal base plate by a support plate, and a counterweight sliding plate further enhances the stability of the suspended structure. The suspended spherical cylindrical phantom is also engraved with lines pointing towards the center of the sphere (center of the ionization chamber matrix) and with lines at distances of 3cm and 5cm from the center. During use, the center of the ionization chamber matrix coincides with the center of the sphere, avoiding the structure of the base plate and horizontal adjustment components. This allows the system to detect radiotherapy doses without considering the influence of the support structure on dose distribution. Additionally, the support plate fixing the spherical cylindrical phantom has a telescopic handle, such as... Figure 6 As shown.

[0019] Preferably, the counterweight assembly 15 includes a counterweight slide plate 15a and a counterweight block 15b disposed on the counterweight slide plate 15a. The counterweight slide plate 15a has several locking slots 16, and the support base 3 has elastic bullseye balls 17. The base plate of the support structure is designed with a counterweight slider, such as... Figure 7 As shown, its end has a counterweight block, which can be pulled out to balance the suspended model when using the ionization chamber matrix model, increasing overall stability. This counterweight slider has three locking slots, which can be fixed in three relative positions by the elastic bullseye on the base plate, greatly reducing the possibility of slide displacement. For example... Figure 8 As shown, the substrate also has a horizontal adjustment component, which has the function of adjusting the level of the suspended mold body.

[0020] Preferably, this radiotherapy dose verification system also includes other functional plug-ins, such as plug-ins for adapting finger-shaped ionization chambers and plug-ins for measuring dose distribution films. When these functional plug-ins are in place, they ensure that the functional center of the plug-in coincides with the center of the spherical cylindrical phantom of the supporting structure, and that their material is consistent with that of the spherical cylindrical phantom—both are uniform ABS equivalent solid water material—facilitating the measurement of radiotherapy doses or image calibration. This system can also be further developed with more plug-ins possessing additional functions according to user needs.

[0021] Preferably, this application also provides a radiotherapy dose verification method based on a spatially distributed multilayer ionization chamber. A novel high-voltage transmission method is used, employing a cylindrical distributed ionization chamber with higher spatial resolution for small radiation field measurement in radiotherapy. Without requiring phantom rotation or angle correction, the dose distribution of radiotherapy radiation at various angles and depths can be acquired and measured simultaneously. The novel high-voltage transmission method is implemented as follows: the ionization chamber matrix phantom 2 is configured to include an ionization chamber matrix component 2a, using a stacked structure of double-layer ionization chambers. A cylindrical distributed ionization chamber matrix is ​​formed by stacking multiple double-layer ionization chambers, with adjacent ionization chambers being high-voltage connected in a spatially staggered manner.

[0022] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. Radiotherapy dose verification system based on spatial volume distributed multilayer ionization chamber, comprising a phantom (1) with a phantom matrix of ionization chambers (2), and a support base (3), characterized in that, The ionization chamber matrix module (2) comprises: An ionization chamber matrix assembly (2a) in a double-layer ionization chamber stacking structure, forming a cylindrical distributed ionization chamber matrix in a manner of stacking each group of double layers and multiple groups, wherein two adjacent groups of ionization chambers are high-voltage connected in a spatially staggered manner; A solid water mold support (2b) for carrying the ionization chamber matrix assembly (2a); A processing circuit (2c) arranged on the solid water mold support (2b) and electrically connected to the ionization chamber matrix assembly (2a).

2. The radiotherapy dose verification system of claim 1, wherein, Each group of ionization chambers comprises a flexible high-voltage plate (4), an outer ring acrylic plate (5), a collection plate (6), and an inner ring acrylic plate (7), the flexible high-voltage plate (4) is composed of a first plate body (4a) and a second plate body (4b) connected to each other, and the ionization chamber is stacked in the order of the first plate body (4a), the outer ring acrylic plate (5), the collection plate (6), the inner ring acrylic plate (7), and the second plate body (4b).

3. The radiotherapy dose verification system of claim 2, wherein, A plurality of high-voltage transmission windows (8) and a plurality of ionization chamber high-voltage windows (9) are arranged on the first plate body (4a) and the second plate body (4b), a plurality of openings are formed on the outer ring acrylic plate (5) and the inner ring acrylic plate (7), and a plurality of collection windows are arranged on the front and back surfaces of the collection plate (6), and in the stacked state, the ionization chamber high-voltage windows (9), the openings, and the collection windows are aligned with each other.

4. The radiotherapy dose verification system of claim 3, wherein, In the stacked state, the ionization chamber high-voltage windows (9) arranged on the first plate body (4a) and the ionization chamber high-voltage windows (9) arranged on the second plate body (4b) are staggered, wherein the ionization chamber high-voltage windows (9) of the first plate body (4a), the openings on the outer ring acrylic plate (5), and the collection windows on the back surface of the collection plate (6) are aligned with each other, and the ionization chamber high-voltage windows (9) of the second plate body (4b), the openings on the inner ring acrylic plate (7), and the collection windows on the front surface of the collection plate (6) are aligned with each other.

5. The radiotherapy dose verification system of claim 4, wherein, A plurality of ionization chamber high-voltage windows (9) are arranged in a ring shape, wherein in the stacked state of a plurality of groups of ionization chambers, the high-voltage transmission windows (8) of a previous group of ionization chambers are aligned with the high-voltage transmission windows (8) of a subsequent group of ionization chambers, after the last group of ionization chambers is stacked, a high-voltage connecting plate (10) is used to connect the ionization chamber matrix and the high-voltage module of the processing circuit (2c), and the collection plate of each group of ionization chambers is electrically connected to the collection and analysis module of the processing circuit (2c).

6. The radiotherapy dose verification system of claim 5, wherein, The first plate body (4a), the second plate body (4b), the outer ring acrylic plate (5), the inner ring acrylic plate (7), and the collection plate (6) are all provided with fixed holes (11) aligned with each other, and a fastening bolt can be nested in the fixed holes (11).

7. The radiotherapy dose verification system of claim 1, wherein, The module (1) and the support base (3) are connected through a support plate (12), the support plate (12) is provided with a handle (13), the support base (3) is provided with a horizontal adjusting member (14) and a counterweight assembly (15), wherein the counterweight assembly (15) can slide in a specified direction.

8. The radiotherapy dose verification system of claim 7, wherein, The counterweight assembly (15) comprises a counterweight sliding plate (15a) and a counterweight block (15b) arranged on the counterweight sliding plate (15a), the counterweight sliding plate (15a) is arranged with a plurality of clamping grooves (16), and the supporting base (3) is arranged with an elastic bullseye (17).

9. The radiotherapy dose verification system of claim 1, wherein, The ionization chamber matrix assembly (2a) is formed by 1020 ionization chambers stacked with each other, has a length of 79.4 mm and a diameter of 104 mm.

10. A method for radiotherapy dose verification based on a spatial volume distributed multi-layer ionization chamber, characterized in that, A new high-voltage transmission mode is adopted, a cylindrical distributed ionization chamber with higher spatial resolution is used for small radiation field measurement in radiotherapy, without rotating the phantom and angle correction, the dose volume distribution of radiotherapy radiation at each angle and depth can be collected and measured at one time, and the new high-voltage transmission mode is realized in the following manner: The ionization chamber matrix phantom (2) is configured to comprise an ionization chamber matrix assembly (2a), a double-layer ionization chamber stacking structure is adopted, a cylindrical distributed ionization chamber matrix is formed in the mode of each group of double layers and multiple groups of stacking, and adjacent two groups of ionization chambers are high-voltage connected in the mode of being spatially staggered with each other.

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