Radioactive source single-source testing device of radiotherapy equipment
By designing a single source physical test device for radiotherapy equipment, the field and dose rate of radiotherapy source passes through the collimator one by one, solving the high-cost physical testing problems in the existing technology, achieving the effect of rapidly optimizing the hole shape of the collimator, and improving the research and development efficiency of radiotherapy equipment.
Patent Information
- Application Number
- CN202421968585.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-14
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2034-08-14
AI Technical Summary
In the prior art, the collimator hole design of the gamma knife needs to be practically verified after simulation, resulting in high physical testing costs and low R&D efficiency.
A single source physical testing device for radiotherapy equipment is designed, including a shielding body, a positioning ring, a plug needle, a connecting frame and a baffle. By testing the field and dose rate of the single source of radiotherapy after passing through the collimator one by one, an ideal collimator hole shape is preferred.
It reduces the cost of physical testing, improves the research and development efficiency of radiotherapy equipment, quickly finds the collimator hole shape that meets the requirements, and optimizes the collimator hole shape design of radiotherapy equipment.
Smart Images
Figure CN223166929U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the medical field, in particular to a method and a device for single-source physical testing of a radiation source of a radiotherapy device. Background Technique
[0002] The gamma knife is a large medical device mainly used for treating craniocerebral diseases and body tumors. Its treatment principle is to collimate and focus the beam of rays through the collimator aperture pattern, so that the focus can obtain a higher dose rate and the required field size. The focus is used to irradiate the lesion site, while the normal tissues around the lesion receive a relatively low dose, thereby improving the curative effect and reducing the damage of radiotherapy to normal tissues. To improve the treatment effect and accuracy of radiotherapy devices, the field size and dose rate when the radiation source emits beams are crucial.
[0003] Currently, in order to obtain an ideal dose rate and field size, the gamma knife usually conducts simulation analysis through a simulation method. Whether the collimator aperture pattern obtained by simulation is really an ideal aperture pattern still needs to be verified through actual tests.
[0004] Currently, the current industry situation is to design and manufacture a collimator with a certain aperture pattern according to simulation, install the collimator on the gamma knife host, and test the focusing effect of the collimator by means of an open-source irradiation film and an ionization chamber. If the field size and dose rate obtained from the physical test are not ideal, it is necessary to redesign and manufacture the collimator, reinstall it and conduct physical tests. The disadvantage of doing this is high cost and long cycle, which reduces the R & D efficiency of radiotherapy devices.
[0005] Therefore, it is necessary to provide a new physical test method and device, which can reduce the physical test cost and improve the R & D efficiency. Summary of the Utility Model
[0006] To solve the above technical problems in the background technique, the utility model provides a single-source physical test device for a radiation source of a radiotherapy device, which can reduce the physical test cost and improve the R & D efficiency for the physical test in the R & D process of the gamma knife of the radiotherapy device.
[0007] The technical solution of the utility model is: a single-source physical test device for a radiation source of a radiotherapy device, which is characterized in that: the single-source physical test device for a radiation source of the radiotherapy device includes a shielding body, a positioning ring, a plug pin, a connecting frame and a baffle; the positioning ring is arranged on the connecting frame, the shielding body is arranged on the positioning ring and passes through the positioning ring, a ray passing hole is arranged in the shielding body, and a plug pin is arranged in the ray passing hole.
[0008] Furthermore, a baffle is arranged at the bottom of the shielding body, and a through hole is arranged at the position of the baffle corresponding to the ray passing hole.
[0009] Furthermore, a first positioning hole is provided on the positioning ring, a connecting plate is provided around the outer side of the middle part of the shielding body, a second positioning hole is provided on the connecting plate corresponding to the position of the first positioning hole, the first positioning hole and the second positioning hole are positioned by positioning screws and locked by nuts.
[0010] Furthermore, there are multiple ray transmission holes, and there are correspondingly multiple through holes.
[0011] Furthermore, there are four radiation transmission holes, which are, from inside to outside, a central radiation transmission hole, an inner circle radiation transmission hole, a sub-outer circle radiation transmission hole and an outer circle radiation transmission hole.
[0012] Furthermore, the baffle is arranged on the bottom of the shielding body through baffle screws.
[0013] Furthermore, the positioning ring is connected to the connecting frame via a set screw.
[0014] Furthermore, connecting screws are provided on the connecting frame.
[0015] A group of radioactive sources in a gamma knife radiotherapy device consists of multiple individual radioactive sources of the same specifications. The size and activity of the individual radioactive sources are known (the radioactive sources have been calibrated when leaving the factory). After the radioactive sources pass through the collimator, the collimation effect of the collimator holes will form a certain size of radiation field and dose rate at the radiation focus point of the gamma knife. The size of this radiation field and dose rate is greatly affected by the size of the collimator hole shape. In order to find a collimator hole with a relatively ideal radiation field and dose rate, multiple collimator holes of different sizes and shapes are designed in a collimator. It is necessary to use a single source test device to test the radiation field and dose rate of the gamma rays passing through each collimator hole at the radiation focus point. The utility model is used in the physical testing of the gamma knife radiotherapy device to test the physical parameters of the multiple individual sources that make up the radiation source one by one using a single source test device. Through comparative analysis of the test data, the hole shape of the multi-hole collimator with better effect can be selected.
[0016] When using the device, the single-source radioactive source test device is installed below the base plate (item 2) of the gamma knife treatment head of the radiotherapy equipment. The device has multiple beam-emitting holes, one of which can be controlled to be in an open state, so that the beam-emitting hole in the open state is aligned with a hole to be tested (item 5) in the collimator (item 4) in the gamma knife treatment head (item 3). There are M holes to be tested in the collimator. Figure 1 After the physical characteristics of one hole to be tested in the collimator are tested, the open hole in the single source test device can be rotated to align with another hole to be tested on the collimator, so that the physical characteristics of multiple holes to be tested in the gamma knife collimator can be tested one by one.
[0017] According to the physical testing method and device provided by the utility model, physical testing costs can be reduced, research and development efficiency can be improved, and a collimator aperture shape that meets the requirements and has good physical properties can be found more quickly.
[0018] By using a single-source physical testing device and testing method, the radiation field and dose rate at the focal point of each single radiation source in a group of radiation sources can be tested after passing through the collimator collimation holes or the holes to be measured. Through comparative analysis, a collimator hole shape with an ideal ray focusing effect can be obtained. This method can be used in the process of optimizing the design of the collimator hole shape and for the design verification of the collimator hole shape of a gamma knife in radiotherapy equipment. Description of the Drawings
[0019] Figure 1 is a schematic structural diagram of the present utility model;
[0020] Figure 2 is a side schematic diagram of the present utility model;
[0021] Figure 3 is an attached schematic diagram of the present utility model;
[0022] Figure 4 is a partial enlarged schematic diagram of the present utility model;
[0023] Figure 5 is a schematic structural diagram of the positioning ring of the present utility model;
[0024] Figure 6 is a vertical cross-sectional schematic diagram of the shielding body of the present utility model Figure 1 ;
[0025] Figure 7 is a vertical cross-sectional schematic diagram of the shielding body of the present utility model Figure 1 ;
[0026] Figure 8 is a cross-sectional schematic diagram of the shielding body of the present utility model;
[0027] Figure 9 is an installation schematic diagram of the present utility model on a gamma knife;
[0028] Figure 10 is a detailed enlarged view of the installation of the present utility model on a gamma knife;
[0029] Figure 11 is a vertical cross-sectional schematic diagram of the collimator of the present utility model Figure 1 ;
[0030] Figure 12 is a vertical cross-sectional schematic diagram of the collimator of the present utility model Figure 2 ;
[0031] Figure 13 is a cross-sectional schematic diagram of the collimator of the present utility model;
[0032] Figure 14It is a schematic structural diagram of the source box;
[0033] Figure 15 It is an attachment diagram of the source box.
[0034] The description of the reference numerals in the drawings is as follows:
[0035] 1. Single-source test device; 2. Bottom plate of the treatment head; 3. Source switch body of the treatment head; 4. Collimator; 5. Test hole; 6. Bearing; 7. Turntable body; 8. Source box; 9. Shielding rod; 10. First shielding body; 11. Drum; 12. Main frame;
[0036] 1.1. Shielding body; 1.2. Positioning ring; 1.3. Plug needle; 1.4. Positioning screw; 1.5. Nut; 1.6. Connecting frame; 1.7. Baffle; 1.8. Baffle screw; 1.9. Set screw; 1.10. Connecting screw; 1.11. Ray passing hole; 1.12. First positioning hole; 1.13. Second positioning hole;
[0037] 1.1.1. Central ray passing hole; 1.1.2. Inner ring ray passing hole; 1.1.3. Sub-outer ring ray passing hole; 1.1.4. Outer ring ray passing hole; 1.1.5. Baffle fastening hole;
[0038] 4.1. Collimator body; 4.2. Lower cover; 4.3. First screw; 4.4. Second screw; 4.5. Upper cover;
[0039] 5.1. Test hole A; 5.2. Test hole B; 5.3. Test hole C; 5.4. Test hole D; 5.5. Test hole E; 5.6. Test hole F; 5.7. Test hole G; 5.8. Test hole H; 5.9. Test hole I; 5.10. First plug needle;
[0040] 8.1. Source box body; 8.2. Radiation source; 8.3. Upper end cover; 8.4. Lower end cover; 8.5. Third screw; 8.6. Fourth screw; Detailed implementation manners
[0041] The present invention will be further described in detail below with reference to the drawings and specific embodiments.
[0042] See Figure 1 、 2, 3, 4, 5, the structure of the specific embodiment of the present utility model includes a shielding body 1.1, a positioning ring 1.2, a plug pin 1.3, a positioning screw 1.4, a nut 1.5, a connecting frame 1.6, a baffle 1.7, a baffle screw 1.8, a set screw 1.9, a connecting screw 1.10, and a radiation through hole 1.11. The positioning ring 1.2 is arranged on the connecting frame, the shielding body 1.1 is arranged on the positioning ring 1.2 and passes through the positioning ring 1.2. A radiation through hole 1.11 is arranged inside the shielding body 1.1, a plug pin 1.3 is arranged inside the radiation through hole 1.11, a baffle 1.7 is arranged at the bottom of the shielding body 1.1, and a through hole is arranged at the position corresponding to the radiation through hole 1.11 on the baffle 1.7. A first positioning hole 1.12 is arranged on the positioning ring, a connecting plate 1.6 is arranged around the outer side of the middle part of the shielding body 1.1, a second positioning hole 1.13 is arranged at the position corresponding to the first positioning hole 1.12 on the connecting plate 1.6, and the first positioning hole 1.12 and the second positioning hole 1.13 are positioned by a positioning screw 1.9 and locked by a nut 1.5.
[0043] The shielding body 1.1 is made of a material with good shielding effect on gamma rays. There are n radiation through holes 1.11 on the shielding body 1.1. The shielding body 1.1 and the positioning ring 1.2 are connected and positioned by a positioning screw 1.4. The positioning ring 1.2 aligns with the positioning hole under the gamma knife treatment head of the radiotherapy device. Adjust the circumferential direction of the positioning ring 1.2. After the correct installation direction of the positioning ring 1.2, the n×ФD1 radiation through holes 1.11 on the shielding body 1.1 will align with the n beam output holes of the collimator on the gamma knife treatment head (n = 4 in this embodiment). The connecting frame 1.6 is fixedly installed under the gamma knife treatment head through a connecting screw 1.10. After the position of the shielding body 1.1 is determined, the positioning ring 1.2 is tightened by a set screw 1.9 installed on the connecting frame 1.6 to fix its position relative to the treatment head of the gamma knife during the whole test process.
[0044] There are M beam output holes in the gamma knife collimator. During the specific test process, among the n holes on the single-source test device 1, only one hole aligns with one beam output hole of the collimator in the gamma knife treatment head, and the other radiation through holes on the shielding body 1.1 are blocked by the plug pin 1.3. The plug pin 1.3 is also made of a material with good shielding effect on gamma rays. The baffle 1.7 is used to prevent the plug pin 1.3 from falling off. There are multiple holes on the baffle 1.7 to allow the radiation of the measured hole to pass through. The baffle screw 1.8 is used to fasten the baffle 1.7. In this way, only when the M holes on the gamma knife treatment head align with the only unblocked radiation through hole of the single-source test device 1 can the beam output, and the other M - 1 holes cannot output the beam, ensuring that among the M holes of the collimator tested for transmission, only the physical parameters of one hole can be detected and are not affected by the other beam output holes of the collimator.
[0045] The using process of the present utility model is as follows:
[0046] 1. Install the collimator for measuring the physical parameters of the hole shape to be measured.
[0047] Refer to Figures 6 - 15 , before testing, the designed holes to be measured, hole A (5.1) to hole I (5.9), need to be installed into the collimator body 4.1. Figure 12 The collimator in the example has a total of 36 positions where the collimating holes 4.6 can be installed. The 36 collimating holes 4.6 are distributed in a multi-ring focusing form. The axes of all the collimating holes 4.6 are focused on one point (the focal point). One of the collimating holes is on the central axis of the collimator, and the remaining 35 collimating holes are equally distributed on 3 concentric circles centered on the central point. There are 15 collimating holes in the outermost ring, 10 collimating holes in the second outermost ring, and 5 collimating holes in the innermost ring. In this example, the holes to be measured are installed in 9 of the collimating holes, and the first plug pins 5.10 are installed in the remaining 27 collimating holes. The first plug pins 5.10 are made of a gamma-ray shielding material (tungsten alloy). The hole shape dimensions of each group of holes to be measured are different, and the specific positions of each group of holes in the collimator need to be recorded. The upper cover 4.5 and the lower cover 4.2 are installed on the upper and lower end faces of the collimator body 4.1, and are installed on the collimator body 4.1 through the second screw 4.4 and the first screw 4.3 respectively.
[0048] Install the assembled collimator 4 and the holes to be measured 5 to the position on the treatment head source switch body 3 where this collimator needs to be installed. For details, refer to Figure 10 , the source switch body is installed in the host treatment head through the bearing 6, and the source switch can be rotated to align the axis of the collimator 4 with the axis of the source cassette 8. And a radiation source 8.2 is installed in the source cassette 8. As shown in Figure 14 , 15 , in this example, 36 radiation sources 8.2 are installed in the source cassette body 8.1. One of them is on the axis of the source cassette, and the remaining 35 radiation sources are equally distributed on 3 concentric circles centered on the central point. There are 20 radiation sources in the outermost ring, 10 radiation sources in the second outermost ring, and 5 radiation sources in the innermost ring. After the axes of the collimator and the source cassette are aligned, each radiation source will align with a hole in the collimator. The activity of each radiation source is recorded, and its position in the source cassette is also recorded. The upper end cover 8.3 and the lower end cover 4.4 are installed on the upper and lower end faces of the source cassette body 8.1, and are installed on the source cassette body 8.1 through the third screw 8.5 and the fourth screw 8.6 respectively. 8.3, upper end cover; 8.4, lower end cover; 8.5, third screw; 8.6, fourth screw;
[0049] The treatment head source switch body 3, the collimator 4, the source cassette 8, the source switch bottom plate 2, the shielding rod 9, the shielding body 10, etc. are all made of gamma-ray shielding materials, which minimize the scattering of gamma rays and make the radiation dose emitted from the collimator holes stable.
[0050] The roller 11 is arranged on the main frame 12, and the turntable body 7 is arranged on the roller 11.
[0051] 2. Install the single-source physical test device onto the gamma knife main unit of the radiotherapy equipment.
[0052] Locate and install the positioning ring 1.2 in the single-source test device 1 by using the positioning holes on the source switch base plate 2. Install the connecting frame 1.6 in the single-source test device 1 to the outer end face of the source switch base plate 2 by using the connecting screw 1.10. The positioning holes are used to determine and adjust the circumferential position of the shielding body 1.1, which can ensure that a hole on the shielding body 1.1 is aligned with a hole on the collimator 4. By using the set screw 1.9 to press against the positioning ring 1.2, the axial position of the positioning ring 1.2 can be ensured to be stable and reliable.
[0053] Install the shielding body 1.1 into the shielding body installation hole of the positioning ring 1.2. Use the positioning screw 1.4 to position the shielding body 1.1 to determine its circumferential position; install the nut 1.5 to fasten the shielding body 1.1 to make its axial position stable.
[0054] 3. Adjust the position of the open hole in this device to align with a hole to be tested in the collimator;
[0055] See Figures 6 - 8, a set of beam output holes are designed on the upper part of the shielding body 1.1, which are distributed in a multi-ring focusing pattern, and the beam output holes have the same focal point as the collimator. Each beam output hole corresponds to a collimating hole on the collimator, where the central beam output hole is aligned with the central collimating hole on the collimator, and one beam output hole is designed for each of the inner ring, the second outer ring, and the outer ring, respectively corresponding to one collimating hole among the collimating holes of each ring of the collimator. A total of 4 beam output holes are designed in this example. A circle of equally divided second positioning holes 1.13 are designed on the edge of the shielding body 1.1, and the number of these second positioning holes 1.13 is a multiple of the number of collimating holes 4.6 in each ring of the collimator 4. The number of second positioning holes 1.13 designed in this example is 20. Unscrew the nut 1.5, remove the shielding body 1.1 downward from the middle hole of the positioning ring 1.2, and rotate the shielding body 1.1 until another second positioning hole 1.13 on the shielding body 1.1 is aligned with the first positioning hole 1.12 of the positioning ring 1.2. At this time, the radiation transmission hole 1.11 of the shielding body 1.1 changes its position relative to the collimator, and the radiation transmission hole 1.11 of the shielding body 1.1 is aligned with other collimating holes 4.6 of the collimator 4, that is, it is beneficial to position the positioning ring 1.2 and the positioning screw 1.4 to reposition the shielding body 1.1, and it can be realized that each collimating hole 4.6 in each ring of the collimating holes 4.6 of the collimator 4 is sequentially aligned with the radiation transmission hole 1.11 of the corresponding ring of the shielding body 1.1. During the test, only one of the four radiation transmission holes 1.11 (the central radiation transmission hole 1.1.1, the inner ring radiation transmission hole 1.1.2, the second outer ring radiation transmission hole 1.1.3, and the outer ring radiation transmission hole 1.1.4) of the shielding body 1.1 emits a beam of rays. Therefore, a plug pin 1.3 (tungsten alloy part) is needed to block the other three radiation transmission holes 1.11 to prevent the output of their rays, and only the dose rate and the field size of the rays passing through the open hole without the plug pin 1.3 at the focal point are tested.
[0056] 4. Adjust the posture of the gamma knife host of the radiotherapy equipment to a position convenient for the single-source physical test of the radiation source;
[0057] Rotate the roller 11 on the gamma knife host to make the treatment head above or on the side of the gantry 12. In this example, the treatment head is above the gantry, and the axis of the collimator is in a vertical state.
[0058] 5. Install a physical test phantom on the treatment couch;
[0059] Install a phantom (head phantom) for physical testing on the treatment couch of the radiotherapy equipment. The head phantom is a spherical standard test phantom, and a film or an ionization chamber can be installed at its center. The film is used to test the field size of the radiation focal point, and the ionization chamber is used to test the dose rate size of the radiation focal point. These are all basic devices and methods in the physical measurement of radiotherapy equipment.
[0060] 6. Since the positional relationship between the treatment couch and the phantom relative to the ray focus point of the host has been obtained during the commissioning of the radiotherapy equipment, the treatment couch can be moved to the center of the phantom to align with the host focus point at this time.
[0061] 7. Install the film for field testing on the test phantom. Operate the gamma knife host to the open source state, irradiate the film installed in the phantom, and then turn off the source. Use the image analysis software to analyze the field size of the radiation passing through the collimator hole to be measured and through the open hole of the single-source test device.
[0062] 8. Install the ionization chamber for physical testing on the test phantom. Operate the gamma knife host to the open source state, use the dose tester to measure the dose rate of the ray passing through the open hole, and then turn off the source.
[0063] 9. Repeat steps 3 - 8 for the field size and dose rate after the remaining collimator holes to be measured.
[0064] 10. Analyze and compare the test results, and select the collimator hole shape size with better physical parameters.
[0065] The technical content not specifically described in the content of the present utility model and the above embodiments is the same as the prior art.
[0066] The above is only the specific implementation manner disclosed by the present utility model, but the protection scope disclosed by the present utility model is not limited thereto. The protection scope disclosed by the present utility model shall be subject to the protection scope of the claims.
Claims
1. A single-source test device for the radiation source of a radiotherapy device, characterized in that: The single-source test device for the radiation source of the radiotherapy equipment includes a shielding body, a positioning ring, a plug pin, a connecting frame and a baffle; the positioning ring is arranged on the connecting frame, the shielding body is arranged on the positioning ring and penetrates through the positioning ring, a ray passing hole is arranged in the shielding body, and a plug pin is arranged in the ray passing hole.
2. The single-source test device for the radiation source of the radiotherapy equipment according to claim 1, characterized in that: A baffle is arranged at the bottom of the shielding body, and a through hole is arranged on the baffle at a position corresponding to the ray passing hole.
3. The single-source test device for the radiation source of the radiotherapy equipment according to claim 2, characterized in that: A first positioning hole is arranged on the positioning ring, a connecting plate is arranged around the outer side of the middle part of the shielding body, a second positioning hole is arranged on the connecting plate at a position corresponding to the first positioning hole, and the first positioning hole and the second positioning hole are positioned by positioning screws and locked by nuts.
4. The single-source testing device for the radiation source of the radiotherapy device according to claim 3, characterized in that: There are multiple ray passing holes, and the through holes correspondingly are multiple.
5. The single-source test device for the radiation source of the radiotherapy equipment according to claim 4, wherein: There are 4 ray passing holes, which are, from the inside to the outside, a central ray passing hole, an inner ring ray passing hole, a sub-outer ring ray passing hole and an outer ring ray passing hole in sequence.
6. The single-source test device for the radiation source of the radiotherapy device according to claim 5, wherein: The baffle is arranged at the bottom of the shielding body through baffle screws.
7. The single-source test device for the radiation source of the radiotherapy equipment according to claim 6, characterized in that: The positioning ring is connected with the connecting frame through set screws.
8. The single-source test device for the radiation source of the radiotherapy device according to any one of claims 1 to 7, characterized in that: Connecting screws are arranged on the connecting frame.