A method and system for complex screening of the dispersion of thermoluminescent detectors

Abstract

This invention provides a method and system for re-screening thermoluminescent detector dispersion. It utilizes medical and industrial radiation source equipment to provide the radiation field for thermoluminescent detector dispersion screening, and optimizes the irradiation geometry of the thermoluminescent detectors, eliminating the dependence on dedicated radiation sources in the dispersion screening process. This significantly lowers the hardware threshold, simplifies the re-screening operation, and improves the overall quality and efficiency of thermoluminescent dose monitoring. By processing the thermoluminescent detector readings, this invention first eliminates thermoluminescent detectors with outlier measurement results, then recalculates the average value of the sampled specimens after outlier removal, calculates the dispersion control range for this batch of thermoluminescent detectors, and finally eliminates thermoluminescent detectors with outlier measurement results again, ensuring the accuracy and reliability of the re-screening results.

Description

Technical Field

[0001] This invention belongs to the field of thermoluminescence detection technology, specifically relating to a method and system for complex screening of the dispersion of thermoluminescence detectors. Background Technology

[0002] A thermoluminescent detector (TLD) is a mixture of thermoluminescent material, or the same material and other non-luminescent materials in a certain weight ratio, with a defined mass, shape, or size. When the detector is irradiated, it absorbs and stores part of the energy of the radiation. When the detector is heated during the measurement process, this energy is released in the form of light. The amount of light emitted when heated is linearly related to the irradiation dose within a certain range.

[0003] Thermoluminescent detectors are the core component of thermoluminescent dosimetry. Within the same batch, detectors exhibit significant differences in sensitivity. Before leaving the factory, manufacturers use a dedicated standard radiation source to screen and group thermoluminescent detectors, grouping those with similar performance together to ensure consistency in measurement results across the entire batch. During use, factors such as storage conditions, annealing and cooling conditions, and frequency of use can cause changes in the performance of thermoluminescent detectors, leading to decreased consistency in measurement results across the batch and affecting the accuracy and reliability of the measurements. Therefore, it is necessary to periodically re-measure the dispersion of thermoluminescent detectors and discard dosimeters with significant deviations to ensure consistent measurement results.

[0004] Currently, most users of thermoluminescent detectors do not conduct re-screening of the detector's dispersion during use. The main reasons for this are as follows:

[0005] (1) Lack of standard radiation source: Most users are not equipped with a dedicated standard radiation source for screening the dispersion of thermoluminescent detectors, and cannot provide a standard radiation field for the rescreening of the dispersion of thermoluminescent detectors.

[0006] (2) Lack of standard guidance methods: There are currently no standard methods to guide the re-screening operation of thermoluminescent detectors, so there are no standard methods to refer to for the re-screening of thermoluminescent detector dispersion. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for complex screening of the dispersion of thermoluminescent detectors, overcoming the aforementioned technical problems existing in the prior art.

[0008] Therefore, the technical solution provided by the present invention is as follows:

[0009] A method for complex screening of the dispersion of thermoluminescent detectors includes the following steps:

[0010] Step 1) Place the tray containing thermoluminescent detectors from the same production batch horizontally and irradiate them with a standard radiation source device; the standard radiation source device operates under rated operating parameters, and the irradiation dose to the thermoluminescent detector is 1-10 mSv.

[0011] Step 2) Store the irradiated thermoluminescent detector;

[0012] Step 3) Randomly select 50-100 thermoluminescent detectors from the same tray as a sample for testing. Measure the results using a thermoluminescent dosimeter reader and calculate the average value of the measured values ​​for the selected thermoluminescent detectors. and standard deviation S Excluding measurement results In addition to thermoluminescent detectors, the average value of the sampled specimens after removing outliers was recalculated. and according to The dispersion control range of this batch of thermoluminescent detectors was obtained. Excluding samples from the random inspection where the measurement results are in Other thermoluminescent detectors;

[0013] Step 4) Read the remaining thermoluminescent detectors in the tray, and the results are in Those that are within the range are retained, and those that are not are discarded, thus completing the re-screening of the thermoluminescent detectors in the entire tray.

[0014] The standard radiation source equipment includes medical digital X-ray imaging equipment, X-ray screen imaging equipment, computer X-ray imaging equipment, X-ray fluoroscopy equipment, digital subtraction angiography X-ray equipment, medical electron linear accelerator, industrial X-ray flaw detector, and industrial electron linear accelerator.

[0015] In step 1), when irradiating with a standard radiation source device, the useful beam emitted by the radiation source device is perpendicular to the plane where the tray is located, so that the distance from the target point of the X-ray tube to the center of the tray is 90-100cm and the center of the tray and the center of the useful beam coincide, and the irradiation field of view is adjusted to the maximum and completely covers the tray.

[0016] Step 2) When storing the irradiated thermoluminescent detector, place it in a lead container or store it in a dark environment without other ionizing radiation sources and at a temperature not exceeding 100°C. The thermoluminescent detectors in different trays should be stored separately for 1-3 days.

[0017] The specific process of step 3) is as follows:

[0018] S1. Randomly select 50-100 thermoluminescent detectors from the same tray for testing and reading, and arrange the tested thermoluminescent detectors in the order of testing.

[0019] S2. Calculate the average value of the sample measurement results. and the standard deviation of the measurement results S ;

[0020]

[0021]

[0022] In the formula, The first sample in the random inspection i Thermoluminescence detector readings, mSv;

[0023] n The number of thermoluminescent detectors sampled for inspection, 50≤n≤100;

[0024] S3. The measurement results of the sampled specimens are... All thermoluminescent detectors other than those specified should be removed; the number of remaining thermoluminescent detectors after removal should not be less than 50, otherwise they should be added.

[0025] S4. Recalculate the average value of the sampled specimens after removing outliers. Calculate the dispersion control range of this batch of thermoluminescent detectors. , ;

[0026] S5. Exclude measurement results from the sampled specimens. Other thermoluminescent detectors;

[0027] S6. Measure the remaining thermoluminescent detector in the tray, and the measurement results are in... Items within the specified range should be retained; otherwise, they should be removed.

[0028] The tray is round or square, with a radius of no more than 10cm for round trays and a side length of no more than 20cm for square trays. The surface of the tray is flat and smooth.

[0029] Before step 1), all thermoluminescent detectors that have undergone re-screening are annealed according to the standard conditions given at the time of manufacture.

[0030] After the thermoluminescent detector is read in S1, if the reading results of more than half of the thermoluminescent detectors in the sample are less than 1.0 mSv or 1 mGy, the thermoluminescent detector is re-annealed and irradiated according to the standard conditions at the time of manufacture; if the reading result given by the thermoluminescent dosimeter reader is a count, it is converted into a dose value using the calibration factor given by the metrology institution, and then a judgment is made.

[0031] When placing thermoluminescent detectors, they should be laid flat in the tray without overlapping or obstructing each other; if the same batch of thermoluminescent detectors to be screened cannot be placed in the same tray, they should be divided into several trays for separate irradiation and screening.

[0032] A thermoluminescent detector dispersion multiple screening system includes a tray, a standard radiation source, and an inspection bed. The standard radiation source is used to provide a standard radiation field for thermoluminescent detector dispersion multiple screening. The inspection bed is used to place the tray containing the thermoluminescent detector. The illumination light from the standard radiation source completely covers the tray.

[0033] The beneficial effects of this invention are:

[0034] The thermoluminescence detector dispersion rescreening method provided by this invention utilizes medical and industrial radiation source equipment to provide a radiation field for thermoluminescence detector dispersion screening, and optimizes the irradiation geometry of the thermoluminescence detector to eliminate the dependence on a dedicated radiation source in the thermoluminescence detector dispersion screening process. This significantly reduces the hardware threshold, simplifies the operation process of thermoluminescence detector rescreening, and improves the overall quality and efficiency of thermoluminescence dose monitoring.

[0035] This invention processes the data read from the thermoluminescent detector, first removing measurement results that are inaccurate or incomplete. In addition to thermoluminescent detectors, the average value of the sampled specimens after removing outliers was recalculated. Calculate the dispersion control range of this batch of thermoluminescent detectors. Then, the measurement results are compared with those of the measurement results. Other thermoluminescent detectors were randomly selected for inspection, and the final decision was made to retain or reject them, ensuring the accuracy and reliability of the rescreening results. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the placement of the thermoluminescent detector tray in an embodiment of the present invention.

[0037] In the picture: 1. Tray; 2. X-ray tube; 3. Examination bed. Detailed Implementation

[0038] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0039] Referring now to exemplary embodiments of the present invention, however, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments is not intended to limit the invention.

[0040] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0041] Example 1

[0042] This invention provides a method for complex screening of the dispersion of thermoluminescent detectors, comprising the following steps:

[0043] Step 1) Place the tray containing thermoluminescent detectors from the same production batch horizontally and irradiate them with a standard radiation source device; the standard radiation source device operates under rated operating parameters, and the irradiation dose to the thermoluminescent detector is 1-10 mSv.

[0044] Step 2) Store the irradiated thermoluminescent detector;

[0045] Step 3) Randomly select 50-100 thermoluminescent detectors from the same tray as a sample for testing. Measure the results using a thermoluminescent dosimeter reader and calculate the average value of the measured values ​​for the selected thermoluminescent detectors. and standard deviation S Excluding measurement results In addition to thermoluminescent detectors, the average value of the sampled specimens after removing outliers was recalculated. and according to The dispersion control range of this batch of thermoluminescent detectors was obtained. Excluding samples from the random inspection where the measurement results are in Other thermoluminescent detectors;

[0046] Step 4) Read the remaining thermoluminescent detectors in the tray, and the results are in Those that are within the range are retained, and those that are not are discarded, thus completing the re-screening of the thermoluminescent detectors in the entire tray.

[0047] This invention ensures the accuracy and reliability of the rescreening results by processing the data read from the thermoluminescent detector.

[0048] Example 2

[0049] Based on Example 1, this example provides a method for complex screening of the dispersion of thermoluminescent detectors. The standard radiation source equipment includes medical digital X-ray imaging equipment, X-ray screen imaging equipment, computer X-ray imaging equipment, X-ray fluoroscopy equipment, digital subtraction angiography X-ray equipment, medical electron linear accelerator, industrial X-ray flaw detector, and industrial electron linear accelerator.

[0050] These standard radiation source devices are widely distributed and easy to operate, significantly reducing the hardware threshold for rescreening work, effectively solving the technical problems encountered by many users in this stage, and improving the overall quality and efficiency of thermoluminescent dosimetry monitoring.

[0051] Example 3

[0052] Based on Example 1, this example provides a method for multiple screening of the dispersion of thermoluminescent detectors. In step 1), when irradiating with a standard radiation source device, the useful beam emitted by the radiation source device is perpendicularly irradiated to the plane where the tray 1 is located, so that the distance from the target point of the X-ray tube to the center of the tray is 90-100cm and the center of the tray 1 coincides with the center of the useful beam. The irradiation field of view is adjusted to the maximum and completely covers the tray 1.

[0053] This embodiment uses a medical digital X-ray imaging device as an example, such as... Figure 1 As shown, place the tray 1 containing the thermoluminescent detector horizontally on the bed surface of the digital X-ray imaging equipment 3 or the floor of the inspection room. Adjust the head of the digital X-ray imaging equipment so that the useful beam irradiates the plane where the tray 1 is located perpendicularly. The distance d from the target point of the X-ray tube 2 to the center of the tray 1 is 100cm. The center of the tray 1 coincides with the center of the useful beam. Adjust the irradiation field of view to the maximum and completely cover the tray 1.

[0054] Operating parameters of digital X-ray imaging equipment:

[0055] a) Tube voltage: Select the most stable tube voltage range between 70kV and 100kV. In this embodiment, 80kV is selected.

[0056] b) Tube current-time product: The commonly used tube current-time product in clinical practice is selected. In this embodiment, 200 mAs is selected.

[0057] Example 4

[0058] Based on Example 1, this example provides a method for multiple screening of the dispersion of thermoluminescent detectors. In step 2), when storing the irradiated thermoluminescent detectors, they are placed in lead containers or stored in a dark environment without other ionizing radiation sources and at a temperature not exceeding 100°C. The thermoluminescent detectors in different trays are stored separately for 1-3 days.

[0059] To ensure the accuracy and reliability of the secondary screening, the thermoluminescent detector should be stored away from other sources of ionizing radiation. Strong light exposure should be avoided during storage, and it should be kept in darkness as much as possible. The storage environment should be dry and clean, and temperatures exceeding 100°C should be avoided. If possible, the thermoluminescent detector can be stored in a lead container. The storage time should ideally be 1 to 3 days, with a minimum of 1 day and a maximum of 5 days.

[0060] Example 5

[0061] Based on Example 1, this example provides a method for complex screening of the dispersion of thermoluminescent detectors. The specific process of step 3) is as follows:

[0062] S1. Randomly select 50-100 thermoluminescent detectors from the same tray 1 for testing and reading, and arrange the tested thermoluminescent detectors in the order of testing.

[0063] S2. Calculate the average value of the sample measurement results. and the standard deviation of the measurement results S ;

[0064]

[0065]

[0066] In the formula, The first sample in the random inspection i Thermoluminescence detector readings, mSv;

[0067] n The number of thermoluminescent detectors sampled for inspection, 50≤n≤100;

[0068] S3. The measurement results of the sampled specimens are... All thermoluminescent detectors other than those specified should be removed; the number of remaining thermoluminescent detectors after removal should not be less than 50, otherwise they should be added.

[0069] S4. Recalculate the average value of the sampled specimens after removing outliers. Calculate the dispersion control range of this batch of thermoluminescent detectors. , ;

[0070] S5. Exclude measurement results from the sampled specimens. Other thermoluminescent detectors;

[0071] S6. Measure the remaining thermoluminescent detector in the tray, and the measurement results are in... Items within the specified range should be retained; otherwise, they should be removed.

[0072] The tray 1 is round or square. The radius of the round tray is no more than 10cm, and the side length of the square tray is no more than 20cm. The surface of the tray 1 is flat and smooth.

[0073] Before step 1), all thermoluminescent detectors that have undergone re-screening are annealed according to the standard conditions given at the time of manufacture.

[0074] If, after measuring the thermoluminescent detector in S1, more than half of the thermoluminescent detectors in the sample have readings less than 1.0 mSv or 1.0 mGy, then the thermoluminescent detectors should be re-annealed and irradiated according to the standard conditions at the time of manufacture.

[0075] After the thermoluminescent detector is read in S1, if the reading result given by the thermoluminescent dosimeter reader is a count, it is converted into a dose value using the calibration factor given by the metrology institution, and then a judgment is made.

[0076] When placing thermoluminescent detectors, they should be laid flat in tray 1 without overlapping or obstructing each other; if the same batch of thermoluminescent detectors to be screened cannot be placed in the same tray 1, they should be divided into several trays 1 for separate irradiation and screening.

[0077] This invention processes the data read from the thermoluminescent detector, first removing measurement results that are inaccurate or incomplete. In addition to thermoluminescent detectors, the average value of the sampled specimens after removing outliers was recalculated. Calculate the dispersion control range of this batch of thermoluminescent detectors. Then, the measurement results are compared with those of the measurement results. Other thermoluminescent detectors were randomly selected for inspection, and the final decision was made to retain or reject them, ensuring the accuracy and reliability of the rescreening results.

[0078] Example 6

[0079] This embodiment provides a thermoluminescent detector dispersion multiple screening system, including a tray, a standard radiation source and an inspection bed. The standard radiation source is used to provide a standard radiation field for thermoluminescent detector dispersion multiple screening. The inspection bed is used to place the tray containing the thermoluminescent detector. The illumination light from the standard radiation source completely covers the tray.

[0080] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A method for complex screening of the dispersion of a thermoluminescent detector, characterized in that: Includes the following steps: Step 1) Place the tray containing thermoluminescent detectors from the same production batch horizontally and irradiate them with a standard radiation source device; the standard radiation source device operates under rated operating parameters, and the irradiation dose to the thermoluminescent detector is 1-10 mSv. Step 2) Store the irradiated thermoluminescent detector; Step 3) Randomly select 50-100 thermoluminescent detectors from the same tray as a sample for testing. Measure the results using a thermoluminescent dosimeter reader and calculate the average value of the measured values ​​for the selected thermoluminescent detectors. and standard deviation S Excluding measurement results In addition to thermoluminescent detectors, the average value of the sampled specimens after removing outliers was recalculated. and according to The dispersion control range of this batch of thermoluminescent detectors was obtained. , Excluding samples from the random inspection where the measurement results are in Other thermoluminescent detectors; Step 4) Read the remaining thermoluminescent detectors in the tray, and the results are in Those that are within the range are retained, otherwise they are discarded, thus completing the re-screening of the thermoluminescent detectors in the entire tray.

2. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 1, characterized in that: The standard radiation source equipment includes medical digital X-ray imaging equipment, X-ray screen imaging equipment, computer X-ray imaging equipment, X-ray fluoroscopy equipment, digital subtraction angiography X-ray equipment, medical electron linear accelerator, industrial X-ray flaw detector, and industrial electron linear accelerator.

3. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 1, characterized in that: In step 1), when irradiating with a standard radiation source device, the useful beam emitted by the radiation source device is perpendicular to the plane where the tray is located, so that the distance from the target point of the X-ray tube to the center of the tray is 90-100cm and the center of the tray and the center of the useful beam coincide, and the irradiation field of view is adjusted to the maximum and completely covers the tray.

4. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 1, characterized in that: Step 2) When storing the irradiated thermoluminescent detector, place it in a lead container or store it in a dark environment without other ionizing radiation sources and at a temperature not exceeding 100°C. The thermoluminescent detectors in different trays should be stored separately for 1-3 days.

5. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 1, characterized in that: The specific process of step 3) is as follows: S1. Randomly select 50-100 thermoluminescent detectors from the same tray for testing and reading, and arrange the tested thermoluminescent detectors in the order of testing. S2. Calculate the average value of the sample measurement results. and the standard deviation of the measurement results S ; In the formula, The first sample in the random inspection i Thermoluminescence detector readings, mSv; n The number of thermoluminescent detectors sampled for inspection, 50≤n≤100; S3. The measurement results of the sampled specimens are... All thermoluminescent detectors other than those specified should be removed; the number of remaining thermoluminescent detectors after removal should not be less than 50, otherwise they should be added. S4. Recalculate the average value of the sampled specimens after removing outliers. Calculate the dispersion control range of this batch of thermoluminescent detectors. , ; S5. Exclude measurement results from the sampled specimens. Other thermoluminescent detectors; S6. Measure the remaining thermoluminescent detector in the tray, and the measurement results are in... Items within the specified range should be retained; otherwise, they should be removed.

6. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 1, characterized in that: The tray is round or square, with a radius of no more than 10cm for round trays and a side length of no more than 20cm for square trays. The surface of the tray is flat and smooth.

7. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 1, characterized in that: Before step 1), all thermoluminescent detectors that have undergone re-screening are annealed according to the standard conditions given at the time of manufacture.

8. The method for complex screening of the dispersion of a thermoluminescent detector according to claim 5, characterized in that: If, after reading the thermoluminescent detector in S1, more than half of the thermoluminescent detectors in the sample have readings less than 1.0 mSv or 1.0 mGy, then the thermoluminescent detectors should be re-annealed and irradiated according to the standard conditions given at the time of manufacture. If the thermoluminescent dosimeter reader gives a count as the measurement result, it is converted into a dose value using the calibration factor provided by the metrology institution, and then a determination is made.

9. A method for complex screening of the dispersion of a thermoluminescent detector according to any one of claims 1-8, characterized in that: When placing thermoluminescent detectors, they should be laid flat in the tray without overlapping or obstructing each other; if the same batch of thermoluminescent detectors to be screened cannot be placed in the same tray, they should be divided into several trays for separate irradiation and screening.

10. A thermoluminescent detector dispersion complex screening system used in the thermoluminescent detector dispersion complex screening method as described in any one of claims 1-9, characterized in that: It includes a tray, a standard radiation source, and an examination bed. The standard radiation source is used to provide a standard radiation field for the dispersion multiple screening of thermoluminescent detectors. The examination bed is used to place the tray containing the thermoluminescent detectors. The illumination light from the standard radiation source completely covers the tray.

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