A medical diagnosis and treatment radionuclide activity traceability measurement method based on gamma spectrum method and related equipment

Abstract

This invention relates to the field of medical radioisotope activity measurement technology. It discloses a method and related equipment for tracing the activity of medical diagnostic radionuclides based on gamma spectroscopy. The method involves using a radioactivity meter to pre-measure the activity of the medical radionuclide solution packaged in a vial until the activity of the tested radionuclide is less than or equal to a preset value. Then, a trace amount of the tested solution is extracted to prepare a polyester film point source. Multiple energy-efficiency fitting curve functions are generated using a gamma spectrometer. The activity of the tested medical radionuclide polyester film point source at each measurement location is calculated. Formula correction and weighted calculation are used to determine the activity value and uncertainty at each location, obtaining the activity of the tested medical radionuclide point source at the first measurement time at the first location. The radionuclide setting of the activity meter is adjusted, and the built-in CAL factor is adjusted until the measured activity matches the activity of the first radionuclide solution, completing the calibration.

Description

Technical Field

[0001] This invention relates to the field of medical radioisotope activity measurement technology, and more specifically, to a method and related equipment for tracing the activity of medical diagnostic radionuclides based on gamma-ray spectroscopy. Background Technology

[0002] Radiopharmaceuticals with promising clinical applications are classified into diagnostic and therapeutic radiopharmaceuticals according to their intended use. For diagnostic radiopharmaceuticals, the nuclide is generally required to emit γ (or X) rays or positrons (β+) at a rate of 100–300 keV, but not β- or α rays. For therapeutic radiopharmaceuticals, the nuclide is required to emit α rays with an energy of less than 6 MeV, β- rays with an energy of less than 1 MeV, and emit internally converted electrons or Auger electrons.

[0003] For medical radiopharmaceuticals to be used clinically, it is essential to ensure the accuracy of their radioactivity, which determines the effective dose given to the patient. In the field of nuclear medicine, the ideal radiopharmaceutical activity is one that allows for accurate imaging or treatment while minimizing radiation exposure and damage to the patient. Typically, the diagnostic / therapeutic activity of radiopharmaceuticals ranges from 1 to 200 mCi (1 mCi = 3.7 × 10⁻⁶ mCi). 7 (Bq) can only be measured using a radioactivity meter. The current status of the traceability process for medical radioactivity meters can be found here. Figure 1 .

[0004] In the commercial field, the instrument used to measure radiopharmaceuticals is the 4πγ ionization chamber radioactivity meter. It requires periodic (usually every two years) traceability before use, but is limited to specific volumes of three specific nuclides (I-131, Tc-99m, and F-18). The instrument's calibration factor is provided as required, and after correction, it can be used to determine the activity of radiopharmaceuticals containing those nuclides. For a large number of other radiopharmaceuticals, traceability can only be performed using the 4πβ-γ activity standard, or by directly calculating decay values ​​based on the activity certificate provided by the foreign manufacturer upon import. The accuracy of these measurements cannot be guaranteed.

[0005] Although the values ​​of radionuclides other than I-131, Tc-99m, and F-18 can be traced using a 4πβ-γ coincidence measurement device, the following problems exist in practice:

[0006] There are few metrology institutions with the capability to perform 4πβ-γ coincidence measurement. In China, only the National Institute of Metrology and the China Institute of Atomic Energy possess this capability.

[0007] The 4πβ-γ coincidence measurement method requires the preparation of a gold-plated thin film source. The sample preparation process is complex and the process control is strict. Depending on the different β-γ emitting nuclides, different efficiency extrapolation models need to be established based on the decay pattern diagram. There are many correction factors, so the measurement cycle is very long and the cost is high.

[0008] The development of nuclear medicine in China is progressing rapidly. According to the outline of the "Medium and Long-Term Development Plan for Medical Isotopes (2021-2025)," the goal is to achieve "one (nuclear medicine) department per county" by 2035. The existing radiopharmaceutical nuclide measurement and traceability technologies and methods are far from meeting the actual needs.

[0009] According to GBZ120-2020 "Standards for Radiation Protection in Nuclear Medicine", the deviation between the measured value and the expected value of the activity of radiopharmaceuticals packaged in human doses should not exceed ±10%. However, the method of this invention can control the deviation to within 5% based on uncertainty assessment, which fully meets the national standard requirements for the accuracy of radiopharmaceutical activity. At the same time, the efficiency is improved and it is easier to promote.

[0010] In view of this, the present invention provides a method and related equipment for tracing the activity of medical diagnostic radionuclides based on gamma spectroscopy. Summary of the Invention

[0011] To overcome the problems in existing technologies, this invention proposes a method and related equipment for tracing the activity of medical diagnostic radionuclides based on gamma-ray spectroscopy, which can solve the problem of traditional radioactivity meters being unable to accurately measure the activity of radionuclides other than those requiring gamma-ray spectroscopy. 131 I, 18 F and 99m The problem of the inability to trace and calibrate the activity of medical therapeutic nuclides that emit gamma rays, other than Tc, is solved by preparing a high-precision point reference source and using a gamma-ray energy spectroscopy weighted algorithm.

[0012] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for tracing the activity of medical therapeutic radionuclides based on gamma-ray spectroscopy, characterized by comprising the following steps:

[0013] Step S1: Set the radioactivity meter to the test nuclide setting, pre-measure the activity of the test medical radionuclide solution packaged in a vial, and define the corresponding medical radionuclide solution as the first nuclide solution;

[0014] Step S2: If the activity of the tested nuclide in the first nuclide solution is greater than the preset nuclide activity, then extract a quantitative amount of the first nuclide solution into a new vial using a pipette, and repeat step S1 until the activity of the tested nuclide in the first nuclide solution is less than or equal to the preset nuclide activity.

[0015] Step S3: If the activity of the measured nuclide in the first nuclide solution is less than or equal to the preset nuclide activity, use a pipette to transfer the first nuclide solution of mass m1 to a new vial, and then use a pipette to extract the first nuclide solution of mass m2 and drop it onto a polyester film to prepare a point source for γ spectrum measurement.

[0016] Step S4: Measure the full-spectrum efficiency of the γ-ray spectrometer at different distances using a multi-nucleoside mixed point source with known activity, and generate energy-efficiency fitting curve functions at different spatial distances;

[0017] Step S5: Place the prepared point source of the nuclide to be tested at multiple efficiency calibration points, and calculate the radioactivity of the point source of the nuclide to be tested, provided that the dead time of the gamma spectrometer meets the requirements.

[0018] Step S6: Based on the decay constant of the nuclide being measured, the gamma spectrum measurement time, and the radioactivity, calculate the activity and combined standard uncertainty at each measurement location;

[0019] Step S7: Based on the formula, correct and weight the activity values ​​and combined standard uncertainty measured at each location to obtain the activity A1 of the medical nuclide point source at the first measurement time at the first location;

[0020] Step S8: Calculate the activity A1 of the medical radionuclide point source to be tested and the activity A2 of the first radionuclide solution in the vial at the time of calibration of the medical radioactivity meter using the formula;

[0021] Step S9: Adjust the nuclide setting of the medical radioactivity meter, use the first nuclide solution in the vial for calibration, adjust the built-in CAL factor of the instrument until the activity measured by the activity meter is consistent, and complete the calibration.

[0022] As a preferred embodiment of the present invention, the vial is a borosilicate vial, and the vial specifications must meet the requirements of an outer diameter of 22.5±0.3mm and a wall thickness of 1.0±0.1mm.

[0023] As a preferred embodiment of the present invention, the preset nuclide activity is 1 mCi.

[0024] As a preferred embodiment of the present invention, the nuclides in the multi-nucleon mixed point source include, but are not limited to, those mentioned above. 241 Am、 137 Cs、 133 Ba, 60 Co and 152 Eu, with an energy range of 59 keV to 1408 keV, has radioactivity values ​​traceable to national standards.

[0025] As a preferred technical solution of the present invention, the energy and efficiency curves of the multi-nucleoside hybrid point source are established at multiple positions in the space directly above the probe by means of a specially designed adjustable positioning bracket.

[0026] As a preferred embodiment of the present invention, step S6 specifically includes the following steps:

[0027] The measurement time is corrected based on the point source activity measured multiple times at different spatial locations by the instrument. Each measurement time is defined as t, and the decay constant of the analyte during the measurement process is λ, where λ = ln2 / T. 1 / 2 T 1 / 2 The half-life of the nuclide being tested;

[0028] Based on the decay constant λ of the analyte, the γ-spectrum measurement time t, and the radioactivity A of the point source of the analyte. 0ij The activity A' of the measured nuclide point source at each measurement position in the γ spectrum corresponding to each measurement time was calculated. 0ij and the activity A of the point source of the measured nuclide at the first measurement time at each measurement location. 1ij The activity at each measurement location is obtained by taking the arithmetic mean. The combined standard uncertainty is u j ;

[0029] The correction method is as follows:

[0030]

[0031]

[0032]

[0033] Among them, A 0ij The activity of the analyte point source at position j, obtained from the i-th measurement, is calculated by the spectrometer based on the energy-efficiency fitting function; A' 0ij Activity after time correction for each measurement at each location; A' 1ij For A' 0ij The activity is corrected to the first measurement time at position j; t' is the time interval between the i-th measurement time at position j and the first measurement time at position j. The average activity value at position j during the first measurement.

[0034] As a preferred embodiment of the present invention, step S7 specifically includes the following steps:

[0035] Based on the formula, the activity values ​​measured at each location and combined standard uncertainty u j ,

[0036] Activity value Corrected to the first position at the time of the first measurement of activity Choose one of the locations for the combined standard uncertainty u j As unit weight variance

[0037] The activity A1 of the medical nuclide point source under test is obtained by performing a weighted calculation based on the formula at the first measurement time of the first location.

[0038] The weighted calculation formula is:

[0039]

[0040]

[0041] Among them, W j The activity weight measured at position j For the activity unit weight variance at the selected location, u j Let j be the combined standard uncertainty of the activity measured at position j.

[0042] As a preferred technical solution of the present invention, step S8 specifically includes the following steps:

[0043] The activity A1 of the medical radionuclide point source is used to calculate the activity A2 of the first radionuclide solution in the borosilicate vial at the time of calibration of the medical radioactivity meter, using the following formula:

[0044]

[0045] Where m1 is the mass of the first nuclide solution in the borosilicate vial; m2 is the mass of the first nuclide solution used to prepare the point source for gamma spectrometer measurement; t2 is the time interval between obtaining the A1 activity and calibrating the activity meter; and t3 is... and The time interval between measurement moments.

[0046] In a second aspect, the present invention provides an electronic device, comprising:

[0047] At least one processor; and

[0048] A memory that is communicatively connected to the at least one processor;

[0049] The memory stores instructions that can be executed by the at least one processor, which, when executed by the at least one processor, cause the electronic device to perform a method for tracing the activity of medical therapeutic radionuclides based on gamma spectroscopy.

[0050] Thirdly, the present invention provides a storage medium storing a computer program thereon, which, when executed by a processor, implements a method for tracing the activity of medical therapeutic radionuclides based on gamma spectroscopy.

[0051] The technical effects and advantages of the present invention, which is a method and related equipment for tracing the activity of medical diagnostic radionuclides based on gamma-ray spectroscopy, are as follows:

[0052] 1) The method of preparing a high-precision polyester thin film point reference source is simpler than the preparation process of VYNS gold-plated thin film in the traditional 4πβ(PC)-γ coincidence method, and the process control requirements and costs are relatively low. Compared with the 4πβ(LS)-γ coincidence method, it does not need to consider the influence of color quenching, chemical quenching and temperature on the technical efficiency of β detector, which reduces the factors affecting uncertainty and greatly shortens the calibration sample preparation time.

[0053] 2) The relative measurement method based on gamma spectrum eliminates the need for coincidence modules and beta detectors in traditional measurement techniques, resulting in a simpler system structure, lower cost, and easier market application while meeting national requirements for the accuracy of radionuclide activity in medical radiotherapy drugs.

[0054] 3) Compared with traditional γ-ray spectroscopy analysis methods, this invention establishes multiple energy-efficiency fitting curve functions in space, performs multiple measurements in time, and then uses a weighted average algorithm on the multiple spatial measurement results, which can significantly reduce the uncertainty of the activity of the tested medical nuclide and improve the accuracy of the activity measurement results.

[0055] 4) The promotion of this technology will provide traceability assurance for radioactive isotopes and radiopharmaceutical research and development and production enterprises, hospital nuclear medicine departments, and metrology and testing institutions for nuclear medicine services, support the implementation of the national medium- and long-term development plan for medical isotopes, and promote the development and construction of "one nuclear medicine department per county". Attached Figure Description

[0056] Figure 1 This diagram illustrates the existing technology for tracing and measuring the activity of therapeutic radionuclides in traditional Chinese medicine. Figure 1 ;

[0057] Figure 2 This diagram illustrates the existing technology for tracing and measuring the activity of therapeutic radionuclides in traditional Chinese medicine. Figure 2 ;

[0058] Figure 3 This is a block diagram of the medical diagnostic radionuclide activity tracing measurement system based on gamma spectroscopy of the present invention;

[0059] Figure 4 This is a flowchart of the measurement value transfer method of the present invention;

[0060] Figure 5 This is an algorithm diagram of the medical diagnostic radionuclide activity tracing measurement method based on gamma spectroscopy according to the present invention;

[0061] Figure 6 This is an algorithm diagram of the medical diagnostic radionuclide activity tracing measurement method based on gamma spectroscopy according to the present invention. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] The following is an explanation of the abbreviations used in this invention:

[0064] 4πγ ionization chamber: A device used to measure radioactivity by means of gamma rays.

[0065] I-131: Iodine-131, a radioactive isotope commonly used to treat or diagnose thyroid problems.

[0066] F-18: Fluorine-18, a radioactive nuclide commonly used in positron emission tomography (PET).

[0067] Tc-99m: Technetium-99m, a radioactive nuclide used in nuclear medicine imaging.

[0068] Uncertainty assessment: The assessment of uncertainty in measurement, used to determine the reliability of measurement results.

[0069] GBZ120-2020: Chinese National Standard "Radiation Protection Standard for Nuclear Medicine", which describes the technology and standards in the fields of medical radiopharmaceuticals and activity measurement.

[0070] Wherein: the module diagram or circuit diagram for gamma ray measurement in the 4πγ ionization chamber is as follows Figure 2As shown, the activity values ​​of three major medical radiopharmaceuticals—I-131, Tc-99m, and F-18—can be traced back to the 4πγ ionization chamber activity standard device (standard-grade radiopharmaceutical) using a relative comparison method with working-grade medical radioactivity meters. However, for the activities of newly developed radiopharmaceuticals such as Sr-89 and Lu-177, which have been developed and prepared in recent years, traceability and transfer can only be achieved through 4πβ-γ coincidence measurement technology. 4πβ-γ coincidence measurement technology is an internationally recognized absolute measurement method. It includes two types of detectors, each detecting one of the two types of radioactive particles emitted during the same decay process. The detector used to detect β particles is called a β detector, which can be a 4π proportional counter (PC) or a liquid scintillation counter (LS). The detector used to detect γ particles is called a γ detector, which can be a high-purity germanium γ spectrometer or a scintillator detector (NaI(Tl)). A coincidence counting system and data processing system are used to measure the radionuclide activity, and then the calibration coefficient is transferred to the radioactivity meter to achieve traceability of the activity values ​​of other radiopharmaceuticals.

[0071] Among them, radioactivity meters are general-purpose radioactivity measuring instruments widely used by radiopharmaceutical manufacturers, hospitals, and isotope research and development institutions. Existing radioactivity meters can measure the activity of hundreds of medical radionuclides. Each nuclide has a built-in CAL coefficient at the time of manufacture, which can be used to roughly estimate the activity of the measured nuclide. However, with continuous use, the sensitivity of the instrument will decrease, and the fixed CAL factor may cause deviations in the results. Therefore, it is necessary to send the instrument to a third-party metrology institution periodically for CAL adjustment to ensure that the final measurement results meet the national requirements for the accuracy of activity meters.

[0072] The activity of the analyte needs to be predicted during calibration. In actual source tracing calibration, the diagnostic radionuclide is measured in a 10ml vial. Therefore, the key point of the method is to determine the activity of the vial source used to calibrate the radioactivity meter. Its activity is determined by the specific activity measured by the point reference source and the mass m of the solution.

[0073] Example 1

[0074] Please see Figures 3-5 As shown in this embodiment, the method for tracing the activity of medical diagnostic radionuclides based on gamma spectroscopy is mainly applied to medical radioisotope and radiopharmaceutical research and development and production enterprises, hospital nuclear medicine departments, and metrology and testing institutions that provide radionuclide activity testing services for medical radiopharmaceuticals. The method includes the following steps:

[0075] Step S1: Set the radioactivity meter to the analyte setting, measure the activity of the medical radioactive nuclide solution packaged in a vial, and label the corresponding medical radioactive nuclide solution as the first nuclide solution;

[0076] It should be noted that the radioactivity meter has built-in settings for up to 100 medical diagnostic nuclides, and a CAL coefficient is preset for each nuclide. When measuring a particular nuclide, the corresponding nuclide setting needs to be selected.

[0077] Step S2: If the activity of the measured nuclide in the first nuclide solution is greater than the preset nuclide activity, extract the first nuclide solution with mass m1 into a new vial using a pipette, repeat step S1, and use a radioactivity meter to measure the activity of the medical radionuclide solution packaged in the borosilicate vial until the solution activity is less than or equal to the preset nuclide activity. At this time, the preset nuclide activity can be 1 mCi.

[0078] It should be noted that when extracting the first nuclide solution using a pipette, the mass should be determined using a balance with a precision of 1 / 1,000,000 to ensure the accuracy of the solution.

[0079] The vial is a borosilicate vial, and the specifications of the borosilicate vial must meet the requirements of an outer diameter of 22.5±0.3mm and a wall thickness of 1.0±0.1mm.

[0080] It should be noted that borosilicate vials serve as containers and transfer tools for radionuclide solutions in medical radioactivity measurements, ensuring the proper handling and accurate measurement of the medical radionuclide solutions. This is crucial for ensuring the safety and efficacy of radiopharmaceuticals; they are used to encapsulate and store medical radionuclide solutions. These solutions contain radionuclides and are used for medical imaging diagnostics or therapeutic purposes.

[0081] When the radioactivity of the solution is greater than 1 mCi, a portion of the solution is extracted from the borosilicate vial using a pipette and transferred to a new vial. This helps to reduce the activity of the solution to meet the requirements of subsequent measurement steps. In step S2, by repeatedly extracting and transferring the solution, it is ensured that the activity of the solution is reduced to less than 1 mCi for subsequent accurate measurements.

[0082] Step S3: When the solution activity is less than the preset nuclide activity, the first nuclide solution is transferred to a new borosilicate vial using a pipette. The mass m1 of the first nuclide solution is weighed using a balance. Then, the mass m2 of the first nuclide solution is extracted using a pipette and dropped onto a polyester film to prepare a point source for γ-spectrum measurement.

[0083] Step S4: Measure the full-spectrum efficiency curve of a high-purity germanium gamma spectrometer at different distances using a multi-nucleon mixture point source with known activity, generating energy-efficiency fitting curve functions at different spatial distances. The multi-nucleon mixture point source contains the following nuclides: 241 Am、 137 Cs、 133 Ba, 60 Co and 152Eu, etc., with an energy range of 59keV to 1408keV, and radioactivity values ​​traceable to national standards.

[0084] Step S5: Place the prepared point source at multiple efficiency calibration points, selected from high to low. Provided the dead time of the gamma spectrometer meets the requirements, each position (j = 1, 2, 3…, m) can be measured multiple times (i = 1, 2, 3…, n). After each measurement, by calling the energy-efficiency fitting curve function, the radioactivity A of the measured nuclide can be obtained based on the characteristic energy peaks of the measured nuclide. 0ij ;

[0085] It should be noted that dead time is a factor affecting the measurement accuracy of high-purity germanium detectors. Generally, a longer dead time will cause a loss in the measured count, meaning the measured count will be smaller than the actual count.

[0086] Step S6: Measurement Time Correction. For medical radionuclides, the half-life is generally short, therefore, the decay of the nuclide during measurement cannot be ignored. Based on the decay constant λ (λ = ln² / T) of the measured nuclide... 1 / 2 T 1 / 2 The half-life of the nuclide being tested), the γ-ray spectrum measurement time t, and the radioactivity A of the point source of the nuclide being tested obtained in step S5 are given. 0ij The activity A' of the measured nuclide point source at each measurement location and time of the γ spectrum was calculated. 0ij and the activity A of the point source of the measured nuclide at the first measurement time at each measurement location. 1ij The activity at each measurement location is obtained by taking the arithmetic mean. The combined standard uncertainties are u j The correction method is as follows:

[0087]

[0088]

[0089]

[0090] Among them, A 0ij The activity of the analyte point source at position j, obtained from the i-th measurement, is calculated by the spectrometer based on the energy-efficiency fitting function; A' 0ij Activity after time correction for each measurement at each location; A' 1ij For A' 0ij The activity is corrected to the first measurement time at position j; t' is the time interval between the i-th measurement time at position j and the first measurement time at position j. The average activity value at position j during the first measurement.

[0091] Step S7: Calculate the activity values ​​measured at each location based on the formula. and combined standard uncertainty u j , activity value Corrected to the first position at the time of the first measurement of activity Choose one of the locations for the combined standard uncertainty u j As the unit weighted variance, the activity is calculated according to the formula to obtain the activity A1 of the medical nuclide point source being measured at the first position and the first measurement time.

[0092]

[0093]

[0094] Among them, W j The activity weight measured at position j For the activity unit weight variance at the selected location, u j Let j be the combined standard uncertainty of the activity measured at position j.

[0095] Step S8: Calculate the activity A2 of the first nuclide solution in the borosilicate vial at the time of calibrating the medical radioactivity meter using the formula: (Formula provided in the original text).

[0096]

[0097] Where m1 is the mass of the first nuclide solution in the borosilicate vial; m2 is the mass of the first nuclide solution used to prepare the point source for gamma spectrometer measurement; t2 is the time interval between obtaining the A1 activity and calibrating the activity meter; and t3 is... and The time interval between measurement moments.

[0098] Step S9: Adjust the radionuclide setting of the medical radioactivity meter to the radionuclide to be measured, then calibrate it using the first radionuclide solution in a borosilicate vial, and adjust the built-in CAL factor of the instrument until the activity measured by the activity meter is A3 = A2, thus completing the calibration.

[0099] The above steps will enable the traceability of radiopharmaceutical nuclides by medical radioactivity meters.

[0100] In step S7, the borosilicate vial is used to calculate the activity of the first nuclide solution, which is very important for calibrating a medical radioactivity meter.

[0101] Example 2

[0102] Based on Example 1, a method for measuring the activity of medical radionuclides based on gamma spectroscopy is further disclosed, taking the traceability of the activity value of medical radionuclides Lu-177 as an example.

[0103] The use of Lu-177 nuclides in combination with various targeting molecules to treat systemic metastatic malignant tumors is a widely recognized revolutionary treatment approach in the medical field, particularly demonstrating excellent therapeutic effects in prostate cancer and neuroendocrine tumors. Its half-life is 6.73 days, and while undergoing β-decay (maximum energy 498 keV, 78.6%), it also produces 208 keV gamma rays (11.0%). Its clinical activity is typically measured by radioactivity meters by isotope manufacturers, packaging companies, and medical institutions. Therefore, users have requested traceability of the radioactivity meter readings for the Lu-177 nuclide range.

[0104] The specific implementation steps are as follows:

[0105] We purchased a vial of borosilicate Lu-177 solution, with an estimated volume of about 5 ml. We set the radioactivity meter to Lu177 and performed an activity prediction, which yielded a result of 48.5 MBq (which can be calculated as 1.83 mCi according to the conversion formula).

[0106] Prepare a new air borosilicate glass vial, place it on a balance of 1 / 1 million, and use a high-precision pipette to extract m1 = 3.2134 g of Lu-177 solution into the medium borosilicate glass vial. Then place it in a radioactivity meter to predict the activity. The result is 28.5 MBq (which is less than 1 mCi according to the conversion formula).

[0107] A Lu-177 polyester film point source was prepared by extracting 10 μL of mother liquor from a borosilicate vial using a high-precision pipette. The mass of the mother liquor used for the point source was m2 = 9.992 mg after preparation, and the time was recorded.

[0108] A gamma spectrometer was used to measure the Lu-177 point source. Measurements were taken by placing the Lu-177 point source at different heights on the positioning support, and the full-spectrum energy-efficiency function was retrieved at each height.

[0109] The energy-efficiency fitting function is as follows:

[0110] ln(eff) = a + b·ln(E) + c·ln(E) 2 +d·ln(E) 3 +e·ln(E) 4 +f·ln(E) 5 +g·ln(E) 6 ;

[0111] At different spatial locations, the corresponding parameters a, b, c, d, e, f, and g differ, allowing for the acquisition of the total energy peak efficiency of the 208 keV gamma-ray peak of the Lu-177 nuclide, and thus the activity A of each measurement. oijThe results are shown in Table 1 below;

[0112] Table 1:

[0113]

[0114] The results obtained from the table above are used to perform time-corrected activity A'. 0ij And corrected to the activity A at the start of measurement at each location. 1ij Evaluate the combined standard uncertainty u j The results are shown in Table 2 below:

[0115] Table 2:

[0116]

[0117] At each location The activity was corrected to the first measurement time at the first location. Then, the uncertainty at one of the locations was selected as the unit weighted variance to calculate the weighted activity and the weighted combined uncertainty (location 3 was selected as the unit weighted variance in this case). The results are as follows:

[0118]

[0119]

[0120] It can be seen that u x (A1)<u i This method can improve the accuracy of measurement results.

[0121] Based on A1, the activity A2 of the mother liquor in the borosilicate vial at the time of calibrating the activity meter is calculated. When t2 = 30 min,

[0122]

[0123]

[0124] Set the built-in CAL coefficient of the radioactivity meter being tested until the displayed value A3 = A2, thus completing the calibration of the activity meter. (Specific steps are as follows...) Figure 6 As shown.

[0125] Example 3

[0126] In an exemplary embodiment, an electronic device is also provided, comprising:

[0127] At least one processor; and

[0128] A memory that is communicatively connected to the at least one processor;

[0129] The memory stores instructions that can be executed by the at least one processor, which, when executed by the at least one processor, cause the electronic device to perform a method for tracing the activity of medical diagnostic radionuclides based on gamma spectroscopy.

[0130] For example, computer-readable storage media can be read-only memory (ROM), random access memory (RAM), compact disc read-only memory (CD-ROM), magnetic tape, floppy disk, and optical data storage devices.

[0131] In an exemplary embodiment, a storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements a method for tracing the activity of medical diagnostic radionuclides based on gamma spectroscopy.

[0132] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0133] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for medical therapeutic radionuclide activity traceability measurement based on gamma spectrometry, characterized in that, Includes the following steps: Step S1: Set the radioactivity meter to the test nuclide setting, pre-measure the activity of the test medical radionuclide solution packaged in a vial, and define the corresponding medical radionuclide solution as the first nuclide solution; Step S2: If the activity of the tested nuclide in the first nuclide solution is greater than the preset nuclide activity, then extract a quantitative amount of the first nuclide solution into a new vial using a pipette, and repeat step S1 until the activity of the tested nuclide in the first nuclide solution is less than or equal to the preset nuclide activity. Step S3: If the activity of the measured nuclide in the first nuclide solution is less than or equal to the preset nuclide activity, use a pipette to transfer the first nuclide solution of mass m1 to a new vial, and then use a pipette to extract the first nuclide solution of mass m2 and drop it onto a polyester film to prepare a point source for γ spectrum measurement. Step S4: Measure the full-spectrum efficiency of the γ-ray spectrometer at different distances using a multi-nucleoside mixed point source with known activity, and generate energy-efficiency fitting curve functions at different spatial distances; Step S5: Place the prepared point source of the nuclide to be tested at multiple efficiency calibration points, and calculate the radioactivity of the point source of the nuclide to be tested, provided that the dead time of the gamma spectrometer meets the requirements. Step S6: Based on the decay constant of the nuclide being measured, the gamma spectrum measurement time, and the radioactivity, calculate the activity and combined standard uncertainty at each measurement location; Step S7: Based on the formula, correct and weight the activity values ​​and combined standard uncertainty measured at each location to obtain the activity A1 of the medical nuclide point source at the first measurement time at the first location; Step S8: Calculate the activity A1 of the medical radionuclide point source to be tested and the activity A2 of the first radionuclide solution in the vial at the time of calibration of the medical radioactivity meter using the formula; Step S9: Adjust the nuclide setting of the medical radioactivity meter, use the first nuclide solution in the vial for calibration, adjust the built-in CAL factor of the instrument until the activity measured by the activity meter is consistent, and complete the calibration.

2. The medical diagnosis and treatment nuclide activity traceability measurement method based on gamma spectrum method according to claim 1, characterized in that, The vials are borosilicate vials, and the vial specifications must meet the following requirements: outer diameter 22.5±0.3mm, wall thickness 1.0±0.1mm.

3. The medical diagnosis and treatment nuclide activity traceability measurement method based on gamma spectrum method according to claim 2, characterized in that, The preset nuclide activity is 1 mCi.

4. The method for tracing the activity of medical therapeutic radionuclides based on gamma spectroscopy according to claim 3, characterized in that, Nuclide mixtures in point sources include, but are not limited to, nuclides. 241 Am、 137 Cs、 133 Ba, 60 Co and 152 Eu, with an energy range of 59 keV to 1408 keV, has radioactivity values ​​traceable to national standards.

5. The medical therapeutic radionuclide activity traceability measurement method based on gamma spectrometry according to claim 4, characterized in that, The energy-efficiency curves of the multi-nucleoside hybrid point source are established at multiple locations in the space directly above the probe using a specially designed adjustable positioning bracket to create energy-efficiency fitting functions.

6. The medical diagnosis and treatment nuclide activity traceability measurement method based on gamma spectrum method according to claim 5, characterized in that, Step S6 specifically includes the following steps: The measurement time is corrected based on the point source activity measured multiple times at different spatial locations by the instrument. Each measurement time is defined as t, and the decay constant of the analyte during the measurement process is λ, where λ = ln2 / T. 1 / 2 T 1 / 2 The half-life of the nuclide being tested; Based on the decay constant λ of the analyte, the γ-spectrum measurement time t, and the radioactivity A of the point source of the analyte. 0ij The activity A' of the measured nuclide point source at each measurement position in the γ spectrum corresponding to each measurement time was calculated. 0ij and the activity A of the point source of the measured nuclide at the first measurement time at each measurement location. 1ij The activity at each measurement location is obtained by taking the arithmetic mean. The combined standard uncertainty is u j ; The correction method is as follows: Among them, A 0ij The activity of the analyte point source at position j, obtained from the i-th measurement, is calculated by the spectrometer based on the energy-efficiency fitting function; A' 0ij The activity, corrected for measurement time, is calculated after each measurement at each location; A′ 1ij For A' 0ij The activity is corrected to the first measurement time at position j; t' is the time interval between the i-th measurement time at position j and the first measurement time at position j. The average activity value at position j during the first measurement.

7. The medical diagnosis and treatment nuclide activity traceability measurement method based on gamma spectrum method according to claim 6, characterized in that, Step S7 specifically includes the following steps: Based on the formula the activity values measured at each position and the combined standard uncertainty u j , The activity values The activity at the first position at the first time of measurement is corrected, and the combined standard uncertainty u of one of the positions is selected j As the unit weight variance, The activity A1 of the medical nuclide point source under test is obtained by performing a weighted calculation based on the formula at the first measurement time of the first location. The weighted calculation formula is: Among them, W j The activity weight measured at position j For the activity unit weight variance at the selected location, u j Let j be the combined standard uncertainty of the activity measured at position j.

8. The medical therapeutic radionuclide activity traceability measurement method based on gamma spectrometry according to claim 7, characterized in that, Step S8 specifically includes the following steps: The activity A1 of the medical radionuclide point source is used to calculate the activity A2 of the first radionuclide solution in the borosilicate vial at the time of calibration of the medical radioactivity meter, using the following formula: Where m1 is the mass of the first nuclide solution in the borosilicate vial; m2 is the mass of the first nuclide solution used to prepare the point source for gamma spectrometer measurement; t2 is the time interval between obtaining the A1 activity and calibrating the activity meter; and t3 is... and The time interval between measurement moments.

9. An electronic device, comprising: include: At least one processor; as well as A memory that is communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor, which are executed by the at least one processor to cause the electronic device to perform the method for tracing the activity of medical therapeutic radionuclides based on gamma spectroscopy as described in any one of claims 1-6.

10. A storage medium having stored thereon a computer program, characterized in that When the computer program is executed by the processor, it implements a method for tracing the activity of medical therapeutic radionuclides based on gamma spectroscopy as described in any one of claims 1 to 6.

Images