Calibration device and calibration method for surface absorbed dose rate of medical beta applicator

Abstract

The invention discloses a medical beta applicator surface absorbed dose rate calibration device and calibration method, and belongs to the field of beta applicator radiation dose calibration. The objective of the invention is to improve measurement accuracy and reduce measurement cost. Comprising a base, a movable sliding rail, a thermoluminescence detector, a detector fixing frame and an applicator fixing frame. The movable sliding rail comprises a bidirectional ball screw and a guide rail which are parallel to each other; the guide rail is connected with two connecting seats in a sliding fit mode in the axial direction of the guide rail, the applicator fixing frame is installed on one connecting seat, and the detector fixing frame is installed on the other connecting seat. The beta applicator is mounted on the applicator fixing frame; the detector fixing frame comprises a baffle plate, the slide glass is fixed on the front surface of the baffle plate, the front surface of the slide glass is provided with a groove matched with the thermoluminescence detector, and the thermoluminescence detector is clamped in the groove; the invention discloses a thermoluminescence detector centering beta applicator. The applicator surface dose rate calibration device is simple in structure and convenient to operate, and accurate and efficient calibration of the applicator surface dose rate is achieved by adjusting the relative position of the source and the thermoluminescence detector.

Description

Technical Field

[0001] The invention belongs to the field of radiation dose calibration of beta applicators, and in particular relates to a device and method for calibrating the surface absorbed dose rate of a medical beta applicator. Background Art

[0002] In the field of medical radiotherapy, applicators are often used for radiotherapy of a specific skin tissue range. In order to ensure the treatment effect and prevent inaccurate doses from causing damage and burns to the patient's skin tissue, the absorbed dose rate on the surface of the applicator must be accurately measured, and the measured value must be calibrated with the relative dose rate provided in the certificate in a timely manner to ensure the effectiveness and safety of the treatment. "Requirements for Nuclear Medicine Radiation Protection" GBZ120-2020 clearly stipulates that the user unit must regularly test and calibrate the air absorbed dose rate on the surface of the applicator. At present, an extrapolated ionization chamber is usually used to calibrate the absorbed dose rate on the surface of the beta applicator. However, due to fixed structural factors such as the electrode distance and window thickness of the extrapolated ionization chamber, it is difficult to approach the surface of the applicator. When the distance between it and the source is extremely small (less than 1mm), it is inconvenient to measure the absorbed dose rate, which affects the measurement accuracy. In addition, the ionization chamber is large in size and requires a high-voltage power supply. The operation is complicated and the measurement cost is high. Summary of the Invention

[0003] The purpose of the present invention is to provide a device and method for calibrating the surface absorbed dose rate of a medical beta applicator, which can improve measurement accuracy and reduce measurement costs.

[0004] The technical solution adopted by the present invention is: a medical beta applicator surface absorbed dose rate calibration device, comprising a base, a movable slide rail, a thermoluminescent detector, a detector fixing frame and an applicator fixing frame;

[0005] The movable slide rail includes a bidirectional ball screw and a guide rail parallel to each other; the two ends of the bidirectional ball screw are rotatably mounted on the base, and the guide rail is slidably connected to two connecting seats along its axial direction, and the two connecting seats are connected to the nuts on the bidirectional ball screw in a one-to-one correspondence; and a locking mechanism is provided for locking the position of the connecting seats on the guide rail;

[0006] The applicator fixing frame is installed on one of the connecting seats, and the detector fixing frame is installed on the other connecting seat; the β applicator is installed on the applicator fixing frame;

[0007] The detector holder includes a vertically arranged PMMA baffle, a PMMA slide is provided on one side of the baffle facing the applicator holder, the slide is fixed to the front of the baffle, and a groove is provided on the front of the slide to match the thermoluminescent detector, and the thermoluminescent detector is snapped into the groove;

[0008] The thermoluminescent detector is aligned with the beta applicator.

[0009] Furthermore, a distance display with a resolution of 0.01mm is fixed on the side wall of the base. The distance display is connected to a rotary encoder via a data cable. The rotary encoder is installed at the end of the bidirectional ball screw. The distance display displays the displacement value obtained by converting the screw rotation angle in real time; and a rocker is provided at the end of the bidirectional ball screw to drive it to rotate.

[0010] Furthermore, the front surface of the thermoluminescence detector is flush with the front surface of the slide.

[0011] Furthermore, the groove includes a central groove arranged in the center of the carrier and N groups of peripheral grooves distributed in an annular manner on the carrier, and all peripheral grooves in each group are evenly distributed around the center of the carrier; N is greater than or equal to 1.

[0012] Furthermore, there are four peripheral grooves in each group.

[0013] Furthermore, it includes a source support for fixing the beta applicator, the source support includes a hand-held rod and a source support plate, and a card slot adapted to the beta applicator is provided at the center of the front of the source support plate, and the beta applicator is fixed in the card slot.

[0014] The method for calibrating the surface absorbed dose rate of a medical beta applicator using the calibration device comprises the following steps:

[0015] Step 1: Select a thermoluminescent detector with appropriate performance based on the dose size of the beta applicator to be calibrated and fully anneal the thermoluminescent detector;

[0016] Step 2: Fix the β applicator to the applicator holder, aligning the center of the source window with the baffle;

[0017] Step 3: Place the annealed thermoluminescence detector in the center groove of the slide, mount the slide to the baffle, and align the center of the β applicator source window with the thermoluminescence detector in the center groove;

[0018] Step 4: Move the connector to the contact position between the source window and the thermoluminescence detector, retract until the distance between the source window and the thermoluminescence detector is 0.1 mm, and lock the connector;

[0019] Step 5: Remove the thermoluminescence detector within 3 seconds after irradiation for 5-10 minutes;

[0020] Step 6: Repeat steps 3-5 to measure the dose rate at other distances between the source window and the TL detector; measure the dose rate when the distance between the source window and the TL detector is less than or equal to 5 mm.

[0021] Step 7: Fit a function curve that conforms to the β exponential decay, and deduce the surface dose rate D0 at d=0 based on the function curve.

[0022] Furthermore, the dose rate uniformity measurement process is:

[0023] First, thermoluminescence detectors are placed synchronously in all the grooves around the slide, and the dose rate at multiple locations is measured in one irradiation. Then, the dose rate uniformity is calculated based on the measured dose rates at each location.

[0024] The measurement of the thermoluminescence detector placed in the peripheral groove is performed synchronously with the measurement of the thermoluminescence detector placed in the central groove.

[0025] Furthermore, the film changing operation time is ≤5s.

[0026] The beneficial effects of the present invention are as follows: the medical beta patch surface absorbed dose rate calibration device disclosed in the present invention uses a thermoluminescent detector to calibrate the beta patch surface absorbed dose rate. Compared with a traditional extrapolated ionization chamber, since the thickness of the thermoluminescent detector is only in the millimeter order, its volume is significantly reduced relative to the extrapolated ionization chamber, and no high-voltage energy source and real-time circuit are required, thereby overcoming the defects of the extrapolated ionization chamber being large in volume and relying on supporting circuits.

[0027] Furthermore, a movable slide composed of parallel bidirectional ball screws and guide rails drives the detector holder and the applicator holder in relative linear motion to meet the required measurement distance between the thermoluminescent detector and the beta applicator, simplifying the motion path and thus the overall structure of the device. Controlling the movement distance by rotating the bidirectional ball screw and locking it with a locking mechanism allows for simple operation and quick distance adjustment. The provision of grooves on the slide and the placement of the slide on the baffle allow for rapid replacement of thermoluminescent detectors. Rapid adjustment and quick slide change reduce the additional exposure associated with these operations, thereby improving measurement accuracy.

[0028] Thermoluminescence detectors offer low single-use costs and can be processed in batches, making them particularly suitable for multi-point distribution measurements. While they require annealing and readout equipment, they offer lower long-term maintenance costs and lack fragile electronic components.

[0029] By measuring dose rates at multiple locations with a single exposure, the uniformity measurement efficiency is greatly improved compared to traditional power room measurements. There is no need to adjust the detection points through mechanical movements such as rotation, which avoids measurement errors caused by the distance deviation between the original window and the detector. All detection points are measured under the same radiation conditions, which improves data comparability and is more conducive to improving measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the main view of the present invention;

[0031] Figure 2 A top view of the present invention;

[0032] Figure 3 Schematic diagram of installing the thermoluminescence detector on the slide;

[0033] Figure 4 The source support main view;

[0034] Figure 5 This is the left view of the source support.

[0035] In the figure, there are base 1, bidirectional ball screw 2, guide rail 3, connecting seat 4, nut 5, applicator fixing frame 6, detector fixing frame 7, baffle 701, carrier 702, central groove 703, peripheral groove 704, rocker 8, source support 9, hand-held rod 901, source support plate 902, card slot 903, thermoluminescence detector 10, β applicator 11, and distance display 12. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments given are not intended to limit the present invention. Unless there is a conflict, the embodiments of the present invention and the technical features in the embodiments may be combined with each other.

[0038] Medical beta applicator surface absorbed dose rate calibration device, such as Figure 1-Figure 5 As shown, it includes a base 1, a movable slide rail, a thermoluminescent detector 10, a detector fixing frame 7 and an applicator fixing frame 6; the movable slide rail includes a bidirectional ball screw 2 and a guide rail 3 parallel to each other; both ends of the bidirectional ball screw 2 are rotatably mounted on the base 1, and the guide rail 3 is an optical axis, which can be square or circular. There are two connecting seats 4 on the guide rail 3 that are slidably fitted along its axial direction. The two connecting seats 4 are connected to the nuts 5 on the bidirectional ball screw 2 in a one-to-one correspondence, that is, Figure 1 As shown, the nut 5 on the left is fixedly connected to the connecting seat 4 on the left, and the nut 5 on the right is fixedly connected to the connecting seat 4 on the right. In this way, when the bidirectional ball screw 2 rotates, the two connecting seats 4 can be driven by the nut 5 to move linearly toward each other or move linearly away from each other. The lead of the bidirectional ball screw 2 is 1mm, and the flatness of the guide rail 3 is ≤0.02mm / m. A locking mechanism is provided for locking the position of the connecting seat 4 on the guide rail 3. After the connecting seat 4 moves linearly along the guide rail 3 to the desired position, the position of the connecting seat 4 is locked by the locking mechanism to ensure that the axial distance between the detector and the source remains unchanged. The locking mechanism can take various forms, such as a locking pin, a caliper, etc.

[0039] The applicator fixing frame 6 is installed on one of the connecting seats 4 , and the detector fixing frame 7 is installed on the other connecting seat 4 ; the β applicator 11 is installed on the applicator fixing frame 6 .

[0040] The detector mounting frame 7 includes a vertically arranged baffle 701. A slide 702 is provided on the front of the baffle 701. The slide 702 is fixed to the front of the baffle 701. The slide 702 has a groove on the front of the baffle 701 that is adapted to fit the thermoluminescent detector 10. The thermoluminescent detector 10 is snapped into the groove. The thermoluminescent detector 10 is aligned with the beta applicator 11.

[0041] Among them, a control rocker 8 is provided at one end of the movable slide rail to drive the movable slide rail to rotate. The control rocker 8 is connected to the bidirectional ball screw 2 through a coupling. The control rocker 8 rotates 360 degrees to push the connecting seat 4 to move 1mm. A distance display 12 is also provided for reading the moving distance. The resolution of the distance display 12 is 0.01mm. The distance display 12 is connected to a rotary encoder via a data cable. The rotary encoder is installed at the end of the bidirectional ball screw 2. The distance display 12 displays the displacement value obtained by converting the screw rotation angle in real time. The rotary encoder is a photoelectric encoder that outputs 3600 pulses per revolution, corresponding to a displacement resolution of 0.01mm. The distance display 12 has a built-in microprocessor that can receive the pulse signal of the rotary encoder, calculate the real-time distance and display it, realizing dynamic high-precision distance reading, ensuring the accuracy of distance adjustment, and reducing the measurement error caused by distance reading deviation.

[0042] The β applicator 11 is fixed by the source support 9, specifically, as Figure 4 and Figure 5 As shown, the source holder 9 includes a handheld rod 901 and a source support plate 902. A slot 903 adapted for the beta applicator 11 is provided at the center of the front of the source support plate 902. The beta applicator 11 is fixed in the slot 903. The applicator fixing frame 6 can be three pillars arranged in a row, and the handheld rod 901 is passed through the three pillars at a time for horizontal fixation.

[0043] The baffle 701 is made of PMMA with a thickness of 1 cm or more to protect against beta radiation and the safety of the operator.

[0044] The "front" mentioned in this specification refers to the relative position relationship, such as: the front of the baffle 701 and the front of the carrier 702 both refer to the side facing the β applicator 11; and the front of the component on the side where the β applicator 11 is located refers to the side facing the thermoluminescence detector 10.

[0045] The thermoluminescence detector 10 is used to measure the ionizing radiation counts in the air at the location of the thermoluminescence detector 10 . The thermoluminescence detector 10 is thin and small in size, with a thickness typically less than 1 mm. For example, the thermoluminescence detector 10 has a specification of 3.2×3.2×0.4 mm.

[0046] Slide 702 is used to secure the thermoluminescent detector 10. Slide 702 is made of PMMA, the same material used to simulate human water tissue. With the thermoluminescent detector 10 mounted, slide 702 is adhered to baffle 701, also made of PMMA, using ultra-thin transparent double-sided tape. This allows the back of the thermoluminescent detector 10 to be entirely PMMA. Together, slide 702 and baffle 701 simulate the surface of human skin being irradiated by beta radiation, creating a favorable testing environment. The front of the thermoluminescent detector 10 is flush with the front of slide 702. That is, the depth of the groove in slide 702 is precisely equal to the thickness of the thermoluminescent detector 10. The groove is also compatible with the thermoluminescent detector 10, meaning that the detector 10 and the groove have the same shape and size, allowing them to fit snugly into the groove. The friction between the two effectively secures the detector 10, allowing it to be moved closer to the surface of the beta source, resulting in more accurate measurements. A film taking gap is provided on the periphery of the groove and is communicated with the groove. Tweezers can be inserted into the film taking gap to take out the thermoluminescent detector 10 .

[0047] The medical beta patch surface absorbed dose rate calibration device disclosed in the present invention uses a thermoluminescent detector 10 to calibrate the beta patch surface absorbed dose rate. Compared with a traditional extrapolated ionization chamber, since the thickness of the thermoluminescent detector 10 is only in the millimeter order, its volume is significantly reduced relative to the extrapolated ionization chamber, and no high-voltage energy source and real-time circuit are required, thereby overcoming the defects of the extrapolated ionization chamber being large in volume and relying on supporting circuits.

[0048] Furthermore, the movable slide rail composed of the mutually parallel bidirectional ball screw 2 and the guide rail 3 drives the detector fixing frame 7 and the applicator fixing frame 6 to move linearly relative to each other to meet the measurement distance control between the thermoluminescent detector 10 and the β applicator 11, simplifying the movement path and thus simplifying the overall structure of the device. By controlling the rotation of the bidirectional ball screw 2 to control the moving distance and cooperating with the locking mechanism for locking, the operation is simple, and the distance data can be read in real time with the corresponding distance display 12, and the distance adjustment can be completed within 10 seconds. The setting of the groove on the carrier 702 and the setting of the carrier 702 being pasted on the baffle can realize the rapid replacement of the thermoluminescent detector 10, and the replacement of each thermoluminescent detector 10 can be completed within 5 seconds. Rapid adjustment and rapid film change reduce the additional exposure caused by the operations of changing and adjusting the films, which is conducive to improving the accuracy of the measurement.

[0049] The thermoluminescence detector 10 offers low single-use costs and can be processed in batches, making it particularly suitable for multi-point distribution measurements. While it requires annealing and readout equipment, it offers lower long-term maintenance costs and contains no vulnerable electronic components.

[0050] The grooves include a central groove arranged at the center of the carrier 702 and N groups of peripheral grooves 704 distributed in a ring shape on the carrier 702, and all peripheral grooves 704 in each group are evenly distributed around the center of the carrier 702; N is greater than or equal to 1. Figure 3 An embodiment of N=1 is given. A thermoluminescent detector 10 is installed in the central groove to measure the dose rate at multiple distance points, and then curve fitting is performed to infer the surface dose rate. Thermoluminescent detectors 10 are installed in the peripheral grooves 704 to measure the uniformity of the active area. With this arrangement, thermoluminescent detectors 10 can be installed in all the peripheral grooves 704 at one time to achieve multi-point synchronous measurement of the active area. Compared with the traditional ionization chamber that requires multiple measurements and rotation adjustment of the source holder, it can cover a wider area of ​​the active area of ​​the β applicator 11, and can perform multi-position measurements at one time, greatly improving the efficiency of uniformity measurement; it also avoids the deviation of the distance between the source window and the detector caused by rotation adjustment, which is conducive to reducing errors; and all detection points are measured under the same radiation conditions, which enhances data comparability.

[0051] The more peripheral grooves 704 there are, the higher the measurement accuracy will be, but the corresponding cost will increase and the data processing will increase. Experiments have shown that setting four peripheral grooves 704 in each group can meet the dual requirements of detection accuracy and cost.

[0052] The method for calibrating the surface absorbed dose rate of a medical beta applicator using the calibration device comprises the following steps:

[0053] Step 1: Select a thermoluminescent detector 10 with appropriate performance according to the dose size of the beta applicator 11 to be calibrated, and fully anneal the thermoluminescent detector 10;

[0054] Step 2: Fix the β applicator 11 to the applicator holder 6, aligning the center of the source window with the baffle 701;

[0055] Step 3: Place the annealed thermoluminescent detector 10 in the central groove 703 of the slide 702. Mount the slide 702 on the baffle 701, and align the source window of the β applicator 11 with the thermoluminescent detector 10 in the central groove 703.

[0056] Step 4: Move the connector 4 to the contact position between the source window and the thermoluminescence detector 10, retract it until the distance between the source window and the thermoluminescence detector 10 is 0.1 mm, and lock the connector 4;

[0057] Step 5: Remove the thermoluminescence detector 10 within 3 seconds after irradiation for 5-10 minutes;

[0058] Step 6: Repeat steps 3-5 to measure the dose rate at other distances between the source window and the thermoluminescence detector 10; the distance between the source window and the thermoluminescence detector 10 is less than or equal to 5 mm. The other distances are 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm.

[0059] Step 7: Fit a function curve that conforms to the β exponential decay, and deduce the surface dose rate D0 at d = 0 based on the function curve. The function can be Among them, the coefficient α and β are derived from specific data, and d is Measure the distance between the source window and the thermoluminescence detector 10. D(d) is the dose rate measured at the distance d.

[0060] The present invention discloses a method for calibrating the absorbed dose rate on the surface of a medical beta patch. This method uses multiple distance points (1-5 mm) for measurement, avoids interference from the beta particle buildup effect, and deduces the surface dose rate through fitting. This method reduces the error in current measurement and calibration of the beta patch surface dose rate, overcoming the difficulty of traditional ionization chambers in making accurate measurements at extremely close distances (<1 mm).

[0061] The process of measuring the dose rate uniformity is as follows: first, thermoluminescent detectors 10 are placed in all the peripheral grooves 704 of the slide 702, and the dose rates at multiple locations are measured at one irradiation; then, the dose rate uniformity is calculated based on the measured dose rates at each location. Uniformity = (D max -D min ) / D 平均 × 100%). D max is the maximum dose rate at each point, D max is the minimum dose rate at each point, D 平均 is the average dose rate measured at all points.

[0062] The measurement of the thermoluminescence detector 10 placed in the peripheral groove 704 is performed synchronously with the measurement of the thermoluminescence detector 10 placed in the central groove 703, that is, the uniformity measurement and the surface dose rate measurement are performed synchronously.

[0063] By measuring dose rates at multiple locations with a single exposure, the uniformity measurement efficiency is greatly improved compared to traditional power room measurements. There is no need to adjust the detection points through mechanical movements such as rotation, which avoids measurement errors caused by the distance deviation between the original window and the detector. All detection points are measured under the same radiation conditions, which improves data comparability and is more conducive to improving measurement accuracy.

[0064] The operation time of changing the thermoluminescence detector 10 in the present invention is ≤5s.

[0065] The film changing time of the present invention is controlled within 5 seconds, and then the time for adjusting the distance between the thermoluminescent detector 10 and the β applicator 11 to the required value by using the joystick is controlled within 1-2 seconds. In this way, the actual measurement irradiation time is increased while ensuring that the total irradiation dose is within the linear range of the thermoluminescent detector 10, and the proportion of additional exposure caused by the operations of film changing and adjustment is reduced.

[0066] The present invention discloses a method for calibrating the surface absorbed dose rate of a medical beta patch. The error range of the surface dose rate of the beta patch is stable at 0.8%-15%. The time required for one calibration is 10-20 minutes, the cost range is 100-200 yuan, and the stability is acceptable.

[0067] Although the present invention is described herein with reference to embodiments, the above embodiments are merely general implementations of the present invention, and the implementations of the present invention are not limited to the above embodiments. It should be understood that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A device for calibrating the surface absorbed dose rate of a medical beta applicator, characterized in that: It comprises a base (1), a movable slide rail, a thermoluminescence detector (10), a detector fixing frame (7) and an applicator fixing frame (6); The movable slide rail comprises a bidirectional ball screw (2) and a guide rail (3) which are parallel to each other; both ends of the bidirectional ball screw (2) are rotatably mounted on the base (1); two connecting seats (4) are connected to the guide rail (3) in a sliding manner along its axial direction; the two connecting seats (4) are connected to the nuts (5) on the bidirectional ball screw (2) in a one-to-one correspondence; and a locking mechanism is provided for locking the connecting seats (4) in position on the guide rail (3); The applicator fixing frame (6) is installed on one of the connecting seats (4), and the detector fixing frame (7) is installed on the other connecting seat (4); the β applicator (11) is installed on the applicator fixing frame (6); The detector fixing frame (7) comprises a baffle (701) made of PMMA material arranged vertically, a carrier sheet (702) made of PMMA material being arranged on a side of the baffle (701) facing the applicator fixing frame (6), the carrier sheet (702) being fixed to the front side of the baffle (701), a groove adapted to the thermoluminescent detector (10) being arranged on the front side of the carrier sheet (702), and the thermoluminescent detector (10) being snapped into the groove; The thermoluminescent detector (10) is aligned with the beta patch (11).

2. The device for calibrating the surface absorbed dose rate of a medical beta patch according to claim 1, wherein: A distance display (12) with a resolution of 0.01 mm is fixed to the side wall of the base (1). The distance display (12) is connected to a rotary encoder via a data line. The rotary encoder is installed at the end of a bidirectional ball screw (2). The distance display (12) displays the displacement value obtained by converting the screw rotation angle in real time. A rocker (8) is provided at the end of the bidirectional ball screw (2) to drive the ball screw to rotate.

3. The device for calibrating the surface absorbed dose rate of a medical beta patch according to claim 1, wherein: The front surface of the thermoluminescent detector (10) is flush with the front surface of the slide (702).

4. The device for calibrating the surface absorbed dose rate of a medical beta patch according to claim 1, 2 or 3, wherein: The grooves include a central groove (703) arranged at the center of the carrier (702) and N groups of peripheral grooves (704) distributed in a ring shape on the carrier (702), and all peripheral grooves (704) in each group are evenly distributed around the center of the carrier (702); N is greater than or equal to 1.

5. The device for calibrating the surface absorbed dose rate of a medical beta patch according to claim 4, wherein: There are four peripheral grooves (704) in each group.

6. The device for calibrating the surface absorbed dose rate of a medical beta patch according to claim 1, 2 or 3, wherein: The invention comprises a source support (9) for fixing the beta applicator (11), wherein the source support (9) comprises a hand-held rod (901) and a source support plate (902), and a card slot (903) adapted to the beta applicator (11) is provided at the center of the front of the source support plate (902), and the beta applicator (11) is fixed in the card slot (903).

7. A method for calibrating the surface absorbed dose rate of a medical beta patch using the calibration device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Selecting a thermoluminescent detector (10) with appropriate performance according to the dose size of the beta applicator (11) to be calibrated, and completely annealing the thermoluminescent detector (10); Step 2: Fix the β applicator (11) to the applicator holder (6) with the center of the source window aligned with the baffle (701); Step 3: placing the annealed thermoluminescent detector (10) in the central groove (703) of the carrier (702), mounting the carrier (702) on the baffle (701), and aligning the source window of the β applicator (11) with the thermoluminescent detector (10) in the central groove (703); Step 4: Move the connecting seat (4) to the contact position between the source window and the thermoluminescence detector (10), withdraw it until the distance between the source window and the thermoluminescence detector (10) is 0.1 mm, and lock the connecting seat (4); Step 5: After irradiation for 5-10 minutes, remove the thermoluminescence detector (10) within 3 seconds; Step 6: Repeat steps 3-5 to measure the dose rate at other distances between the source window and the thermoluminescence detector (10); the distance between the source window and the thermoluminescence detector (10) is less than or equal to 5 mm; Step 7: Fit a function curve that conforms to the β exponential decay, and deduce the surface dose rate D0 at d=0 based on the function curve.

8. The method for calibrating the surface absorbed dose rate of a medical beta patch according to claim 7, wherein: Including dose rate uniformity measurement, the measurement process is: First, thermoluminescence detectors (10) are synchronously placed in all peripheral grooves (704) of the carrier (702), and the dose rates at multiple locations are measured during one irradiation; then, the dose rate uniformity is calculated based on the measured dose rates at each location; The measurement of the thermoluminescence detector (10) placed in the peripheral groove (704) is performed synchronously with the measurement of the thermoluminescence detector (10) placed in the central groove (703).

9. The method for calibrating the absorbed dose rate on the surface of a medical beta patch according to claim 8, wherein: The film changing operation time is ≤5s.

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