Quality control motif for heavy ion treatment and testing method thereof

Abstract

The invention discloses a quality control motif for heavy ion therapy and a testing method thereof, the quality control motif is a cube, and at least one edge of the cube is cut off; a rectangular inclined surface is arranged on the quality control die body at the position where the edge is cut off, and one short edge and the other opposite short edge of the rectangular inclined surface are respectively positioned on two opposite side surfaces of the quality control die body; and the distance from the rectangular inclined plane to the die body original point of the quality control die body is equal to the distance from the surface of the quality control die body, which takes the long side of the rectangular inclined plane as the common side, to the die body original point. According to the invention, dosimetry data of measurement beams of the quality control die body at 0 degree, 90 degrees and preset angles can be obtained only by placing the quality control die body once, so that a tester does not need to enter a test machine room for multiple times to replace the quality control die body in a test process, the number of times of exposing the quality control tester under induced radiation is reduced, and the exposure risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of equipment calibration, and in particular to a quality control phantom for heavy ion therapy and a testing method thereof. Background Art

[0002] Heavy ion therapy is an advanced technology that uses heavy ion beams (such as carbon and helium ions) for tumor radiotherapy. To ensure the accuracy of heavy ion therapy, quality control testing is essential. This testing systematically examines equipment performance, dose distribution, and treatment procedures to minimize errors.

[0003] Quality control testing for heavy ion therapy requires the use of test phantoms. Existing test phantoms typically use solid water phantoms, which are composed of multiple stacked phantoms. When testing different treatment heads, the phantoms need to be stacked in different ways, so that their surfaces are perpendicular to the incident heavy ion beam. The entire process involves stacking the solid water phantoms in different ways. These phantoms are then scanned using a specific scanning protocol, such as a CT scanner, and the scan data is transmitted to the treatment planning system. A radiotherapy plan is created, and theoretical values ​​(or calculated values) for the test points are calculated. The solid water phantoms are then stacked in a manner appropriate for a specific head. The treatment plan is then implemented, and the dose data is measured using an ionization chamber. These data are then compared with the calculated values ​​to verify the performance of the heavy ion system.

[0004] During dosimetric validation of different handpieces, testers must repeatedly enter the quality control testing room to adjust the stacking arrangement of the solid water phantoms. However, heavy ion therapy generates harmful induced radiation, exposing testers to this radiation whenever they approach the solid water phantoms. While existing procedures establish strict experimental specifications, manual labor still presents safety risks. Minimizing personal exposure to induced radiation is particularly crucial for those dedicated to heavy ion therapy quality control testing. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a quality control phantom and a testing method thereof for heavy ion therapy, so as to avoid exposure of quality control testers to induced radiation as much as possible and reduce exposure risks.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: A quality control phantom for heavy ion therapy, wherein the quality control phantom is a cube, and at least one edge of the cube is truncated; The position where the edge of the quality control phantom is truncated has a rectangular inclined surface, and one short side and another opposite short side of the rectangular inclined surface are respectively located on two opposite side surfaces of the quality control phantom; The rectangular slope has a preset inclination angle, and the distance from the rectangular slope to the phantom origin of the quality control phantom is equal to the distance from the surface of the quality control phantom with the long side of the rectangular slope as a common side to the phantom origin.

[0007] In order to solve the above technical problems, another technical solution adopted by the present invention is: A method for testing a quality control phantom for heavy ion therapy is implemented using the above-mentioned quality control phantom for heavy ion therapy, the method comprising: S1. Place the quality control phantom at a preset position in the test room, with the side of the quality control phantom adjacent to the long side of the rectangular slope as the top surface; S2. Control the heavy ion device to emit heavy ion beams to the quality control phantom from the top surface facing the quality control phantom, the side adjacent to the other long side of the rectangular slope, and the rectangular slope, and measure dose data using an ionization chamber.

[0008] The beneficial effects of the present invention are: providing a quality control phantom for heavy ion therapy and a testing method thereof, setting a quality control phantom with a rectangular slope at a preset angle, keeping the distances from the rectangular slope and other sides of the quality control phantom except the rectangular slope to the phantom origin of the quality control phantom equal, so that when conducting quality control tests on heavy ion therapy, only one placement is required to obtain the dose data of the quality control phantom measuring the beam at 0°, 90° and preset angles, so that the tester does not need to enter the test room multiple times to re-place the quality control phantom during the test process, thereby reducing the number of times the quality control tester is exposed to induced radiation and reducing the exposure risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A three-dimensional image of a quality control phantom for heavy ion therapy according to the present invention during quality control scanning; Figure 2 A three-dimensional image of a quality control phantom for heavy ion therapy according to the present invention when collecting a reference image; Figure 3 A schematic diagram of a quality control phantom for heavy ion therapy according to the present invention being irradiated with a 0° beam during quality control testing; Figure 4 A schematic diagram of a quality control phantom for heavy ion therapy according to the present invention being irradiated by a 45° beam during quality control testing; Figure 5 A schematic diagram of a quality control phantom for heavy ion therapy according to the present invention being irradiated by a 90° beam during quality control testing; Figure 6 This is a schematic structural diagram of a quality control phantom for heavy ion therapy according to the present invention having multiple contoured sockets; Figure 7 A schematic diagram of the relative positions of a quality control phantom and a phantom block for heavy ion therapy according to the present invention; Figure 8 Schematic diagram of the steps of a testing method for a quality control phantom for heavy ion therapy according to the present invention.

[0010] Description of labels: 1. Quality control phantom; 2. Rectangular bevel; 3. Contoured jack; 4. Solid push rod; 5. Cross-shaped scale; 6. Identification piece; 7. Phantom block. DETAILED DESCRIPTION

[0011] To illustrate the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and accompanying drawings.

[0012] Please refer to Figures 1 to 7 , a quality control phantom for heavy ion therapy, wherein the quality control phantom 1 is a cube, and at least one edge of the cube is truncated; The position where the edges of the quality control phantom 1 are truncated has a rectangular inclined surface 2, and one short side and the other opposite short side of the rectangular inclined surface 2 are respectively located on two opposite side surfaces of the quality control phantom 1; The inclination of the rectangular slope 2 is a preset angle, and the distance from the rectangular slope 2 to the phantom origin of the quality control phantom 1 is equal to the distance from the surface of the quality control phantom 1 with the long side of the rectangular slope 2 as the common side to the phantom origin.

[0013] From the above description, it can be seen that the beneficial effect of the present invention is that: a quality control phantom 1 is set with a rectangular slope 2 with a preset angle, and the distances from the rectangular slope 2 and the other sides of the quality control phantom 1 except the rectangular slope 2 to the phantom origin of the quality control phantom 1 are kept equal, so that when performing quality control testing of heavy ion therapy, only one placement is required to obtain the dose data of the quality control phantom 1 at 0°, 90° and preset angles. This makes it unnecessary for the test personnel to enter the test room multiple times to rearrange the quality control phantom 1 during the test, thereby reducing the number of times the quality control test personnel are exposed to induced radiation and reducing the exposure risk.

[0014] Furthermore, the quality control phantom 1 is provided with a shaped insertion hole 3 on the other side surfaces except the rectangular inclined surface 2 at a position corresponding to the origin of the phantom; The depth of the profiling socket 3 is such that when the balancing cap is fully inserted into the profiling socket 3 , the center of the scale ring on the balancing cap coincides with the origin of the model.

[0015] As can be seen from the above description, the contoured socket 3, located at the phantom origin on the quality control phantom 1, is used to accommodate the balancing cap. This ensures that the center of the scale ring on the balancing cap strictly coincides with the phantom origin. During heavy ion therapy quality control testing, the coincidence of the center of the balancing cap's scale ring with the phantom origin ensures a stable physical environment for the dose calculation reference point, improving the accuracy of dose measurement and beam calibration, and ensuring that quality control data more closely matches the dose distribution scenario experienced during clinical treatment.

[0016] Furthermore, it also includes a solid push rod 4; The solid push rod 4 is adapted to the contoured socket 3 .

[0017] From the above description, it can be seen that the solid push rod 4 is adapted to the contoured socket 3. After the solid push rod 4 is fully inserted, the entire quality control phantom 1 no longer has an internal cavity and can be regarded as a complete solid structure.

[0018] Furthermore, the quality control phantom 1 and the solid push rod 4 are both made of polymethyl methacrylate.

[0019] As can be seen from the above description, the quality control phantom 1 and solid push rod 4 are made of polymethyl methacrylate (PMMA, commonly known as organic glass). This material has excellent water equivalence, and its physical parameters, such as density and effective atomic number, are close to those of water. Using PMMA to construct the quality control phantom 1 and solid push rod 4 more realistically simulates the transport and energy deposition of heavy ions in water, making dose measurements and beam characteristic verification during quality control testing more reliable, providing a high-quality simulation foundation for accurate clinical treatment planning.

[0020] Furthermore, cross-shaped scales 5 are provided on the side surfaces of the quality control phantom 1 except the rectangular inclined surface 2 , and the intersection origin of the cross-shaped scales 5 corresponds to the projection of the phantom origin on the side surface.

[0021] As can be seen from the above description, a cross-shaped scale 5 is provided on the side of the quality control phantom 1, with the intersection corresponding to the phantom origin. During heavy ion therapy quality control testing, this scale allows for quick and intuitive alignment of the phantom with the external laser light (the beam system's coordinate system is expressed through the external laser light), improving the efficiency and accuracy of quality control testing.

[0022] Furthermore, an identification piece 6 for identification by image software is provided at the intersection origin of the cross-shaped scale 5 .

[0023] As can be seen from the above description, the intersection of the cross-shaped scale 5 and the origin point are located on an identifier 6 that can be identified by imaging software. In heavy ion therapy quality control, combined with image-guided technology (such as digital radiography (DR)), the imaging software can quickly and automatically identify the phantom origin. This enables automated, digital calibration of phantom positioning, reducing manual positioning errors and significantly improving positioning consistency, especially during repeated testing or multi-batch testing of phantoms.

[0024] Furthermore, the identification member 6 is located on another side surface of the quality control phantom 1 opposite to the side surface where the contoured socket 3 is located.

[0025] From the above description, it can be seen that on the one hand, the centroid can be quickly identified from one direction using image software through the identification piece 6, and on the other hand, the balancing cap can be physically positioned from another direction with the help of the contoured socket 3.

[0026] Furthermore, the preset angle is 45°.

[0027] As can be seen from the above description, the preset angle is set to 45°. This angle is typical of the common oblique incidence angles used in heavy ion therapy quality control (for example, for certain tumors, the beam must be incident at an angle to avoid irradiating organs). Using a phantom with a 45° bevel, a single placement allows for simultaneous verification of the dose characteristics of multiple beam orientations, including 0° (vertical incidence), 90° (horizontal incidence), and 45° (oblique incidence), covering common clinical beam angle scenarios.

[0028] Please refer to Figure 8 A method for testing a quality control phantom for heavy ion therapy is implemented using the above-mentioned quality control phantom for heavy ion therapy, the method comprising: S1, placing the quality control phantom 1 at a preset position in the test room, with the side of the quality control phantom 1 adjacent to the long side of the rectangular slope 2 as the top surface; S2. Control the heavy ion device to emit heavy ion beams to the quality control phantom 1 from the top surface facing the quality control phantom 1, the side adjacent to the other long side of the rectangular slope, and the rectangular slope, and measure the dose data using an ionization chamber.

[0029] From the above description, it can be seen that the beneficial effect of the present invention is that: a quality control phantom 1 is set with a rectangular slope 2 with a preset angle, and the distances from the rectangular slope 2 and the other sides of the quality control phantom 1 except the rectangular slope 2 to the phantom origin of the quality control phantom 1 are kept equal, so that when performing quality control testing of heavy ion therapy, only one placement is required to obtain the dose data of the quality control phantom 1 at 0°, 90° and preset angles. This makes it unnecessary for the test personnel to enter the test room multiple times to rearrange the quality control phantom 1 during the test, thereby reducing the number of times the quality control test personnel are exposed to induced radiation and reducing the exposure risk.

[0030] Furthermore, before S2, the step further includes: In combination with the cross-shaped scale 5 and the identification piece 6 on the quality control phantom 1 , the position of the quality control phantom 1 is calibrated by a laser positioning device, and a reference image of the quality control phantom 1 is collected at the same time.

[0031] As can be seen from the above description, before testing, the phantom position is calibrated using a laser positioning device, combined with the cross-shaped scale 5 and the marker 6, and a reference image is captured. Laser positioning quickly establishes a precise relationship between the phantom and the treatment room coordinate system. The marker 6 and the scale-assisted image software accurately identify the phantom origin, and the reference image serves as a baseline for comparison of the phantom position in subsequent tests.

[0032] Please refer to Figures 1 to 7 , embodiment 1 of the present invention is: A quality control phantom for heavy ion therapy is disclosed. The quality control phantom 1 is a cube with at least one truncated edge. A rectangular bevel 2 is located on the quality control phantom 1 at the location of the truncated edge. One short side and the other opposite short side of the rectangular bevel 2 are located on two opposite sides of the quality control phantom 1. The rectangular bevel 2 has a preset inclination angle, and the distance from the rectangular bevel 2 to the phantom origin of the quality control phantom 1 is equal to the distance from the surface of the quality control phantom 1 that shares the long side of the rectangular bevel 2 to the phantom origin. Furthermore, a contoured socket 3 is provided on each side of the quality control phantom 1, excluding the rectangular bevel 2, at a position corresponding to the phantom origin. The inner bottom of the contoured socket 3 overlaps with the phantom origin, and the contoured socket 3 is used to accommodate a balancing cap.

[0033] In this embodiment, if Figure 1 As shown, the quality control phantom 1 is obtained by cutting off one edge of a 150×150×150 mm cube, and a rectangular slope 2 is formed at the same time as the edge is cut off; Figure 2 and Figure 3The inclination of rectangular slope 2 is a preset angle. The distance D3 from rectangular slope 2 to the origin of quality control phantom 1 is equal to the distances (D1 and D2) from the surface of quality control phantom 1 shared by the long side of rectangular slope 2 to the origin of the phantom. That is, the distances from the top surface of quality control phantom 1, the surface adjacent to the other long side of the rectangular slope, and rectangular slope 2 to the origin of the phantom are equal, specifically 100 mm. To accommodate heavy ion therapy heads at various angles, the inclination of rectangular slope 2 can be designed to other angles besides 45°, such as 30°.

[0034] In this embodiment, if Figure 6 As shown, the number of the contoured jacks 3 can be two or more; and, only one contoured jack 3 satisfies the above-mentioned condition that the distances D1, D2, and D3 are equal, and the other contoured jacks 3 can still be used for quality control testing even if they do not meet this condition.

[0035] Combine Figure 7 As shown, this embodiment also provides one or more phantom blocks 7; the shape of the phantom block 7 is similar to the surface formed by the rectangular slope 2 of the quality control phantom 1 and the surface with the long side of the rectangular slope 2 as the common side; when in use, the phantom block 7 also corresponds to the rectangular slope 2 and the surface with the long side of the rectangular slope 2 as the common side, and is used to increase the distance from the ionization chamber to the phantom surface of the quality control phantom 1 during heavy ion therapy testing, thereby measuring dose data at different depths.

[0036] At the same time, the quality control phantom 1 is also provided with a solid push rod 4. The quality control phantom 1 and the solid push rod 4 are both made of polymethyl methacrylate; in addition, they can also be made of materials such as polystyrene that have radiological properties similar to water.

[0037] In this embodiment, if Figure 2 As shown, the quality control phantom 1 is provided with cross-shaped scales 5 on all sides except the rectangular slope 2. The intersection of the cross-shaped scales 5 corresponds to the projection of the phantom origin onto the side. An identification element 6 for image software recognition is located at the intersection of the cross-shaped scales 5. The identification element 6 is located on the side of the quality control phantom 1 opposite the side where the contoured receptacle 3 is located. The identification element 6 can be made of a tungsten bead (preferably with a diameter of 1 to 1.5 mm). Other materials with high atomic numbers can also be used to achieve high image contrast.

[0038] Please refer to Figures 1 to 8 , the second embodiment of the present invention is: A method for testing a quality control phantom for heavy ion therapy, such as Figure 8 As shown, a quality control phantom for heavy ion therapy according to the first embodiment is implemented, and the method includes: S1. Place the quality control phantom 1 at a preset position in the test room, with the side of the quality control phantom 1 adjacent to the long side of the rectangular inclined surface 2 as the top surface; In this embodiment, the long sides of the rectangular inclined surface 2 refer to the upper and lower sides of the inclined surface of the rectangular inclined surface 2. Figure 2 As shown, in combination with the cross-shaped scale 5 and the identification piece 6 on the quality control phantom 1, the position of the quality control phantom 1 is calibrated by a laser positioning device, and a reference image of the quality control phantom 1 is collected at the same time, specifically including: After the quality control phantom 1 is positioned and before the imaging process begins, the marker 6 is mounted on the cross-shaped scale 5. The laser positioning device is then aligned with the cross-shaped scale 5. After the phantom is aligned, two sets of digital images are acquired. Using the established reference image generation software, the marker 6 is identified in both sets of digital images to determine the center point, and a new reference image is then acquired. The newly generated reference image is stored in a designated system folder.

[0039] It should be noted that the purpose of acquiring reference images is to perform imaging quality control using the quality control phantom 1 of this embodiment. After positioning the quality control phantom 1 relative to the laser light, images from the DR are acquired to determine whether there is any deviation between the laser light and the DR. Therefore, the quality control phantom 1 of this embodiment is a multifunctional phantom, capable of both determining whether there is any deviation between the laser light and the DR and collecting dose data as described below. However, the identification element 6 plays a role only in determining whether there is any deviation between the laser light and the DR and is irrelevant to collecting dose data.

[0040] S2. Insert the ionization chamber with the balance cap into the shaped socket, control the heavy ion device to emit heavy ion beams to the quality control phantom 1 from the top surface facing the quality control phantom 1, the side adjacent to the other long side of the rectangular slope, and the rectangular slope, and use the ionization chamber to measure the dose data.

[0041] In this embodiment, combined with Figure 1 , and 3 to Figure 5 As shown, the top surface of the quality control phantom 1, the side adjacent to the other long side of the rectangular slope, and the rectangular slope 2 correspond to the following angles respectively: 0 degrees: represents the situation where the beam is incident vertically along a straight line. This is the most basic beam direction. In many treatment plans, the beam will be incident in a similar direction. Testing this angle can verify the basic performance of the device under conventional linear irradiation, such as dose output and beam stability.

[0042] 45 degrees: This is an oblique incidence angle, which can examine the equipment's ability to control beam transmission, scanning, and dose distribution in non-horizontal and vertical directions, and verify whether the beam can accurately reach the predetermined position and maintain dose accuracy during the oblique transmission process.

[0043] 90 degrees: Horizontal incidence. For some areas that need to be treated from a specific horizontal direction (such as the treatment of certain tumors in the head and neck), testing at this angle can evaluate the performance of the device in the horizontal direction, such as positioning accuracy and dose conformity.

[0044] In this embodiment, the quality control phantom 1 is scanned using a Siemens CT scanner using a chest scanning protocol (tube voltage 120 kV, tube current 180 mA, slice thickness 1 mm) (the solid push rod of the phantom is pulled out and the balancing cap of the ionization chamber is inserted, but the ionization chamber is not inserted), and the scan data is transmitted to the treatment planning system.

[0045] In addition, in the treatment planning system, three rectangular planning target volumes (PTVs) with uniform size but different depths are created for each test case: shallow PTV, middle PTV, and deep PTV, thus covering all energy levels.

[0046] The region of interest (ROI) is defined as the space occupied by the sensitive volume of the Farmer ionization chamber when the ionization chamber with the balancing cap is fully inserted into the phantom. In the planning system, the material of the ROI is assigned to water (the ROI is originally air, which is very easy to distinguish in CT images). Then, a radiotherapy plan is created and the average dose of the ROI is recorded (denoted as ) During the quality control test, the ionization chamber with the balancing cap is inserted into the contoured socket, and the quality control phantom 1 is aligned by the positioning laser so that the center of the positioning ring on the balancing cap, the origin of the phantom and the origin of the treatment room coordinate system coincide. It can be calculated by the formula: ; in, M Q is the electrometer reading after temperature and pressure correction, N D,w is the water absorbed dose calibration coefficient, k Q is the beam quality factor (according to TRS-398 report, the PTW30013 Farmer ionization chamber is taken as 1.028).

[0047] Every morning test volume D w,Q , calculate the average value of the morning inspection data for five consecutive days, and record it as .

[0048] Will (the average of the five measurements above) and (calculated value) comparison, you can evaluate the accuracy of the planning system calculation; the Dw,Q and By comparing the average of the five measurements above, the daily stability of the gravimetric ion system output dose can be evaluated.

[0049] In summary, the present invention provides a quality control phantom for heavy ion therapy and a testing method thereof, which sets a quality control phantom with a rectangular slope at a preset angle, and keeps the distances from the rectangular slope and other sides of the quality control phantom except the rectangular slope to the phantom origin of the quality control phantom equal, so that when performing quality control testing of heavy ion therapy, only one placement is required to obtain the dose data of the quality control phantom at 0°, 90° and preset angles. This makes it unnecessary for testers to enter the test room multiple times to rearrange the quality control phantom during the test process, thereby reducing the number of times quality control testers are exposed to induced radiation and reducing exposure risks. In addition, a cross-shaped scale is set on the side of the quality control phantom, and the intersection origin corresponds to the phantom origin. In addition, the phantom can also be used to determine whether there is a deviation between the laser light and DR.

[0050] In addition, the phantom is relatively small in size, and even if there are residual induced rays, it can be wrapped in a lead coat and moved away. In comparison, solid water is often larger and difficult to be completely wrapped in an ordinary lead coat and moved away.

[0051] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A quality control phantom for heavy ion therapy, characterized in that: The quality control phantom is a cube, and at least one edge of the cube is truncated; The position where the edge of the quality control phantom is truncated has a rectangular inclined surface, and one short side and another opposite short side of the rectangular inclined surface are respectively located on two opposite side surfaces of the quality control phantom; The rectangular slope has a preset inclination angle, and the distance from the rectangular slope to the phantom origin of the quality control phantom is equal to the distance from the surface of the quality control phantom with the long side of the rectangular slope as a common side to the phantom origin.

2. A quality control phantom for heavy ion therapy according to claim 1, characterized in that: The quality control phantom is provided with a contoured socket on the other side surfaces except the rectangular inclined surface, corresponding to the position of the phantom origin; The depth of the profiling socket is such that when the balancing cap is fully inserted into the profiling socket, the center of the scale ring on the balancing cap coincides with the origin of the mold body.

3. A quality control phantom for heavy ion therapy according to claim 2, characterized in that: Also included are solid push rods; The solid push rod is matched with the contoured socket.

4. A quality control phantom for heavy ion therapy according to claim 3, characterized in that: The quality control phantom and the solid push rod are both made of polymethyl methacrylate.

5. A quality control phantom for heavy ion therapy according to claim 2, characterized in that: Cross-shaped scales are provided on the other side surfaces of the quality control phantom except the rectangular inclined surface, and the intersection origin of the cross-shaped scales corresponds to the projection of the phantom origin on the side surface.

6. A quality control phantom for heavy ion therapy according to claim 5, characterized in that: An identification piece for identification by image software is provided at the intersection origin of the cross-shaped scale.

7. A quality control phantom for heavy ion therapy according to claim 6, characterized in that: The identification part is located on another side surface of the quality control phantom that is opposite to the side surface where the contoured socket is located.

8. The quality control phantom for heavy ion therapy according to claim 1, characterized in that: The preset angle is 45°.

9. A method for testing a quality control phantom for heavy ion therapy, implemented using the quality control phantom for heavy ion therapy according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: S1. Place the quality control phantom at a preset position in the test room, with the side of the quality control phantom adjacent to one of the long sides of the rectangular slope as the top surface; S2. Control the heavy ion device to emit heavy ion beams to the quality control phantom from the top surface facing the quality control phantom, the side adjacent to the other long side of the rectangular slope, and the rectangular slope, and measure dose data using an ionization chamber.

10. The method for testing a quality control phantom for heavy ion therapy according to claim 9, wherein: The S1 also includes: In combination with the cross-shaped scale and the identification piece on the quality control phantom, the position of the quality control phantom is calibrated by a laser positioning device, and a reference image of the quality control phantom is collected at the same time.

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