Alpha nuclide activity inversion method based on energy spectrum analysis and alpha nuclide activity calculation method

Abstract

This paper discloses an alpha nuclide activity inversion method based on energy spectrum analysis. The method involves acquiring the energy spectrum and identifying peak positions of the alpha nuclide to be detected, thereby locating characteristic peaks. Based on these characteristic peaks, the net area of ​​the region of interest is calculated to obtain the net count of characteristic peaks. Geometric and detection efficiency corrections are performed on the detector to obtain the corrected detection efficiency. Based on the net count of characteristic peaks, the corrected detection efficiency, and the system activity time and radioactivity balance correction factor, the parent activity of the alpha nuclide is calculated. This method solves the problem of activity calculation errors caused by insufficient resolution in existing equipment, which cannot distinguish overlapping peaks. Furthermore, an alpha nuclide activity calculation method is disclosed, ensuring that the measurement system maintains high linearity and accuracy over an extremely wide dynamic range (from micro-Curie to Curie levels), achieving full coverage of measurements for both conventional and novel alpha nuclides.

Description

Technical Field

[0001] This invention relates to the field of alpha nuclide activity detection technology, and more specifically, to an alpha nuclide activity inversion method and an alpha nuclide activity calculation method based on energy spectrum analysis. Background Technology

[0002] Currently, the two main types of activity meters are: high-dose gamma source activity meters based on ionization chambers and micro-amplitude meters, and gamma counters based on gamma energy spectrum analysis, which are used for counting / activity measurement of low-activity gamma sources.

[0003] The high-dose activity measurement system based on a well-type ionization chamber and a weak galvanometer has the following technical limitations: This technology operates in current mode. It cannot distinguish the energy of the incident radiation and can only measure the total ionization effect. If the operator selects the wrong nuclide button (e.g., selecting Tc-99m instead of I-131), the reading will be completely incorrect. Furthermore, it is ineffective for alpha nuclides because alpha particles cannot penetrate the metal wall of the ionization chamber, and the gamma rays accompanying alpha decay are often very weak, making the signal easily drowned out by electronic noise, resulting in an extremely low signal-to-noise ratio. Therefore, this type of ionization chamber, which measures in current mode, cannot accurately and reliably measure the activity of alpha and beta nuclides.

[0004] Gamma counters based on gamma spectral analysis have the following technical limitations: This technology operates in "pulse mode." On one hand, there are range limitations and dead time: when the radioactive source activity is high (e.g., exceeding 10 μCi or 370 kBq), a large number of pulses accumulate, causing detector nonlinearity until saturation and no further response, and the count rate no longer increases linearly with activity. Therefore, it is completely unsuitable for measuring therapeutic-grade (mCi / Ci level) radiopharmaceuticals. Furthermore, high-resolution HPGe detectors require liquid nitrogen or complex electrocooling systems, are bulky, and difficult to integrate into routine hospital drug administration procedures.

[0005] For alpha and beta nuclides, some nuclear radiation laboratories and metrology units use liquid scintillation systems to measure their activity. Due to the unique nature of liquid scintillation measurements, the radioactive source to be measured needs to be dissolved in the scintillation fluid. Therefore, a precise sampling and transfer process is required, and the radioactive source and scintillation fluid must be disposed of together after measurement. Thus, only specific laboratories and metrology units can choose to calibrate using this method.

[0006] Therefore, there is an urgent need for an alpha nuclide inversion method and an alpha nuclide activity calculation method that can be matched with a new detector capable of accurately detecting alpha nuclide activity, in order to solve the problems existing in the current technology. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide an alpha nuclide activity inversion method based on energy spectrum analysis, and an alpha nuclide activity calculation method to solve the problems existing in the prior art.

[0008] According to a first aspect of the present invention, a method for inverting the activity of α nuclides based on energy spectrum analysis is provided, comprising: Energy spectrum acquisition and peak position identification are performed on the alpha nuclide to be detected, thereby locating the characteristic peaks; Based on the characteristic peaks, the net area of ​​the region of interest is calculated to obtain the net count of characteristic peaks; The detector is geometrically and detection efficiency is corrected to obtain the corrected detection efficiency; The parent activity of the α nuclide is calculated based on the net count of the characteristic peaks, the corrected detection efficiency, the system live time, and the radioactivity balance correction factor.

[0009] Preferably, the calculation of the parent activity of the α nuclide based on the net count of the characteristic peaks, the corrected detection efficiency, and the system live time and radioactivity balance correction factor includes: Building maternal activity Computational model:

[0010] Net count of characteristic peaks, The system's live time has been automatically corrected for dead time. This represents the emission probability of the characteristic gamma ray. The corrected detection efficiency. It is a radioactive balance correction factor. This is the self-absorption correction factor of the container wall for low-energy gamma rays.

[0011] Preferably, the energy spectrum acquisition and peak position identification of the α nuclide to be detected, thereby locating the characteristic peaks, includes: Energy spectrum of the alpha nuclide to be detected The characteristic peak is located using a peak-finding algorithm.

[0012] Preferably, based on the characteristic peaks, the net area of ​​the region of interest is calculated to obtain the net count of characteristic peaks, including: energy of characteristic peak Set the left and right regions of interest ( Calculate the net peak area count :

[0013] in For channel counting, This is the estimated Compton scattering background.

[0014] Preferably, the net peak area count is calculated using the trapezoidal background subtraction method or the polynomial fitting background method. .

[0015] Preferably, the characteristic peak is located using the Gaussian derivative method.

[0016] Preferably, the detector undergoes geometric and detection efficiency correction to obtain the corrected detection efficiency, including: Absolute detection efficiency of the detector It is energy Heyuan-Exploration Distance The function, based on measurements from the built-in rangefinder. By calling the preset efficiency calibration curve, the corrected detection efficiency can be obtained:

[0017] in This is the solid angle factor at the current distance.

[0018] According to a second aspect of the present invention, a method for calculating the activity of an α-nucleoside is provided, comprising: The activity mode of the α nuclide to be detected is determined based on the real-time collected count rate and current value. If the activity mode is determined to be a low activity mode, the low activity mode algorithm is executed; if the activity mode is determined to be a high activity mode, the high activity mode algorithm is executed. The low and high activity mode algorithms execute the above-mentioned α nuclide activity inversion method based on energy spectrum analysis.

[0019] Preferably, the high-activity mode algorithm includes: The ionization chamber current is calculated, and the activity is calculated based on the collected current value to obtain the activity value based on the current value. The activity value based on the current is calculated as: current value × scale factor. Output the current-based activity value.

[0020] Preferably, the method further includes: qualitatively identifying the α-nucleus to be detected before outputting the current-based activity value.

[0021] Beneficial effects: An Alpha Nuclide Activity Inversion Method Based on Energy Spectrum Analysis: This embodiment presents an alpha nuclide activity inversion method and calculation model based on energy spectrum analysis. For alpha therapeutic nuclides such as Ac-225, which have small gamma-ray branching ratios and complex decay chains, the method utilizes a built-in high-resolution detector to accurately identify and extract characteristic gamma-ray full-energy peaks (e.g., the 218 keV peak) of specific daughter nuclides (e.g., Fr-221) from complex mixed energy spectra, effectively eliminating Compton scattering and other interfering peaks. Based on the long-term radioactive equilibrium between the parent and daughter nuclides, and combined with the detector's absolute detection efficiency and specific branching ratio parameters, the system constructs a mathematical model to infer the total activity of the parent alpha nuclide from the net area of ​​the daughter nuclide's characteristic peaks. This solves the problem of existing equipment failing to distinguish overlapping peaks due to insufficient resolution, leading to incorrect activity calculations.

[0022] Alpha nuclide activity calculation method: The core invention lies in the system's dual-mode automatic switching and range fusion control logic, protecting an intelligent control strategy based on signal strength. The alpha nuclide activity calculation method automatically switches between "current measurement mode" and "pulse counting energy spectrum mode" based on the real-time monitored radioactive signal intensity. When measuring high-activity samples, the alpha nuclide activity calculation method prioritizes ionization chamber current readings to avoid detector dead-time effects; when measuring low-activity samples or requiring nuclide identification, it automatically activates the energy spectrum analysis function of the high-resolution detector. This control logic ensures that the measurement system maintains high linearity and accuracy over an extremely wide dynamic range (from micro-Curie to Curie levels), achieving full coverage of measurements for both conventional and novel alpha nuclides. Attached Figure Description

[0023] The above and other objects, features and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings.

[0024] Figure 1 This is a flowchart of the steps of an exemplary embodiment of the present invention for the method of inverting the activity of α nuclides based on energy spectrum analysis.

[0025] Figure 2 This is a flowchart of the steps of an exemplary embodiment of the present invention for calculating the activity of α-nucleotides.

[0026] Figure 3 This is a schematic diagram of the decay chain of Ac-225 and its daughter products provided by an exemplary embodiment of the present invention.

[0027] Figure 4 This is a characteristic energy spectrum provided by an exemplary embodiment of the present invention (marking the 218keV peak and interference peak used for calculation).

[0028] Figure 5 This invention provides an exemplary embodiment that measures the energy spectrum of Ra223 with different activities, and the measurement results are linearly correlated under different activities. Detailed Implementation

[0029] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0030] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0031] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0032] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0033] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0034] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0035] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0036] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0037] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0038] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0040] This invention targets alpha nuclides such as Ac-225 and Ra-223. Instead of directly measuring alpha particles, this invention utilizes the characteristic gamma rays released when short-lived daughter particles in their decay chains reach either secular or transient equilibrium to establish an inversion mathematical model. See also... Figure 3 and Figure 4 A schematic diagram and characteristic energy spectrum of the decay chain of Ac-225 and its daughter products.

[0041] The physical model is based on the decay of a parent nuclide A (such as Ac-225) to produce a daughter nuclide B (such as Fr-221). And after enough time ( After this, the activities of the daughter and parent organisms reach equilibrium. At this point, the activity of the parent organism A can be calculated by measuring the characteristic gamma rays of the daughter organism B.

[0042] The alpha nuclide activity inversion method based on energy spectrum analysis and the alpha nuclide activity calculation method in this invention can be applied to alpha nuclide activity meters as algorithms for activity calculation.

[0043] This invention provides a method for inverting the activity of alpha nuclides based on energy spectrum analysis, and a method for inverting the activity of alpha nuclides based on daughter body characteristic energy spectrum analysis. See [link to relevant documentation]. Figure 1 This includes the following steps S01)-S04): S01) Perform energy spectrum acquisition and peak position identification on the α nuclide to be detected, thereby locating the characteristic peak; In this step, the system collects the energy spectrum. Characteristic peaks can be located using peak-finding algorithms (such as the Gaussian derivative method).

[0044] For example, for Ac-225, the system automatically identifies the 218 keV characteristic peak of its daughter product Fr-221w, which has a high yield and is relatively independent. See details in [link to documentation]. Figure 3-4 .

[0045] For Ra-223, the system locks in a peak at 269 keV or 154 keV.

[0046] S02) Based on the characteristic peaks, the net area of ​​the region of interest is calculated to obtain the net count of characteristic peaks; energy of characteristic peak Set the left and right regions of interest ( The net peak area count was calculated using either the trapezoidal background subtraction method or the polynomial fitting background method. :

[0047] in For channel counting, This is the estimated Compton scattering background. This step effectively eliminates the interference of Compton plateaus generated by other high-energy gamma rays on the low-energy characteristic peaks.

[0048] S03) Perform geometric and detection efficiency corrections on the detector to obtain the corrected detection efficiency; The detector mentioned in this step is a component of the alpha nuclide activity meter, which is located at a predetermined distance below the ionization well of the alpha nuclide activity and is used to detect the energy spectrum signal of gamma rays from the source to be measured.

[0049] Absolute detection efficiency of the detector It is energy Heyuan-Exploration Distance The function. The system uses the distance measured by the built-in rangefinder. By calling the preset efficiency calibration curve, the corrected detection efficiency can be obtained:

[0050] in The solid angle factor at the current distance, source-detector distance. The source in the image is the emission source, and the detector is the detector.

[0051] S04) Based on the net count of the characteristic peaks, the corrected detection efficiency, the system live time, and the radioactivity balance correction factor, the parent activity of the α nuclide is calculated.

[0052] Based on the above parameters, construct the maternal activity. Computational model:

[0053] Net count of characteristic peaks.

[0054] The system's live time has been automatically corrected for dead time. This refers to the emission probability (branching ratio) of the characteristic gamma rays. For example, the branching ratio of Fr-221 at 218 keV is approximately 11.4%.

[0055] : Corrected detection efficiency.

[0056] Radioactive equilibrium correction factor.

[0057] This is the key to the algorithm. If the drug solution has just undergone chemical separation (such as rinsing from the generator) and the daughter products have not yet reached equilibrium, this factor is less than 1.

[0058] The system allows users to input "production time" or "separation time" and automatically calculates the current growth factor based on the Bateman equation. .

[0059] For most clinical finished drugs (which have been stored for several hours). .

[0060] The container wall (glass / plastic) has a self-absorption correction factor for low-energy gamma rays (usually close to 1 for rays above 200keV, but needs correction for low-energy rays). The container here refers to the vessel that holds the radioactive source.

[0061] A method for calculating the activity of parent α nuclides by inversely estimating the gamma spectrum of daughter nuclides under non-equilibrium or equilibrium conditions.

[0062] See Figure 5 Using the CZT energy spectrum system, the energy spectrum of Ra223 with different activities was measured. The activity of the source under test was calculated by using the count rate in the region of interest (ROI) of the characteristic peak based on the mathematical model established by Ra223 decay law. The measurement results under different activities were linearly correlated.

[0063] The alpha nuclide activity inversion method and calculation model based on energy spectrum analysis in this embodiment, targeting alpha therapeutic nuclides such as Ac-225 with small gamma-ray branching ratios and complex decay chains, utilizes a built-in high-resolution detector to accurately identify and extract characteristic gamma-ray full-energy peaks (such as the 218 keV peak) of specific daughter nuclides (such as Fr-221) from complex mixed energy spectra, effectively eliminating Compton scattering and other interfering peaks. Based on the long-term radioactive equilibrium law between the parent and daughter nuclides, combined with the absolute detection efficiency of the detector and specific branching ratio parameters, the system constructs a mathematical model to infer the total activity of the parent alpha nuclide from the net area of ​​the daughter nuclide's characteristic peaks, solving the problem of existing equipment's inability to distinguish overlapping peaks due to insufficient resolution, which leads to incorrect activity calculations.

[0064] This invention also discloses a method for calculating the activity of α-nucleotides, see [link to relevant documentation]. Figure 2 This includes the following steps S1)-S2): S1) Determine the activity mode of the α nuclide to be detected based on the real-time collected count rate and current value; Based on the real-time detected count rate (CPS) and current value (Amps), the system executes the following logic: High activity mode (> 1 mCi): Reads the ionization chamber current. Using the formula Calculate the activity. If the calculated activity value... If the activity level is greater than the activity threshold, it is determined to be a high activity mode; otherwise, it is determined to be a low activity mode (< 1 mCi), or an alpha nuclide mode. In this case, the energy dispersive spectrometer is only used for qualitative identification of nuclide types and does not participate in quantitative calculations to avoid dead time affecting accuracy.

[0065] S2) If the activity mode is determined to be a low activity mode, then the low activity mode algorithm is executed; if the activity mode is determined to be a high activity mode, then the high activity mode algorithm is executed. The low activity mode algorithm executes the above-mentioned α nuclide activity inversion method based on energy spectrum analysis.

[0066] In this step, the high-activity mode algorithm includes: The ionization chamber current is calculated, and the activity is calculated based on the collected current value to obtain the activity value based on the current value. The activity value based on the current is calculated as: current value × scale factor. Output the current-based activity value.

[0067] This step also includes qualitatively identifying the alpha nuclide to be detected before outputting the current-based activity value. Here, the energy dispersive spectrometer is only used to determine the type of nuclide; this prevents the hospital from mistakenly using the wrong nuclide type for someone else in the past.

[0068] For the specific steps regarding the low activity mode, please refer to the aforementioned method for inverting the activity of alpha nuclides based on energy spectrum analysis, which will not be repeated here.

[0069] This embodiment protects the control logic of a measurement system: the system monitors current signals and pulse count rates in real time. When the signal strength exceeds a preset threshold... At times, the reading from the ionization chamber is the primary indicator; when the signal is below the threshold... When identified as a specific weak photon alpha nuclide, the weights are automatically switched to the output of the energy spectrum inversion algorithm, thereby achieving high linearity measurement across the entire range (equivalent current from fA level to μA level).

[0070] In this embodiment, the core invention lies in the system's dual-mode automatic switching and range fusion control logic, protecting an intelligent control strategy based on signal strength: the alpha nuclide activity calculation method automatically switches between "current measurement mode" and "pulse counting energy spectrum mode" according to the real-time monitored radioactive signal intensity. When measuring high-activity samples, the alpha nuclide activity calculation method preferentially uses the ionization chamber current reading to avoid detector dead-time effects; when measuring low-activity samples or when nuclide identification is required, the energy spectrum analysis function of the high-resolution detector is automatically activated. This control logic ensures that the measurement system maintains high linearity and accuracy over an extremely wide dynamic range (from micro-Curie level to Curie level), achieving full coverage of measurements of both conventional and novel alpha nuclides.

[0071] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0072] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0073] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0074] The methods and apparatus of this disclosure may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0075] It should also be noted that in the apparatus, devices, and methods of this disclosure, the components or steps are decomposable and / or recombinable. Such decomposition and / or recombination should be considered equivalent to the present disclosure. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0076] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A method for inverting the activity of α-nuclides based on energy dispersive spectroscopy, characterized in that, include: Energy spectrum acquisition and peak position identification are performed on the alpha nuclide to be detected, thereby locating the characteristic peaks; Based on the characteristic peaks, the net area of ​​the region of interest is calculated to obtain the net count of characteristic peaks; The detector is geometrically and detection efficiency is corrected to obtain the corrected detection efficiency; The parent activity of the α nuclide is calculated based on the net count of the characteristic peaks, the corrected detection efficiency, the system live time, and the radioactivity balance correction factor.

2. The method for inverting α-nucleus activity based on energy spectrum analysis according to claim 1, characterized in that, Based on the net count of the characteristic peaks, the corrected detection efficiency, and the system live time and radioactivity balance correction factor, the calculation of the parent activity of the α nuclide includes: Building maternal activity Computational model: Net count of characteristic peaks, The system's live time has been automatically corrected for dead time. This represents the emission probability of the characteristic gamma ray. The corrected detection efficiency. As a radioactive balance correction factor, This is the self-absorption correction factor of the container wall for low-energy gamma rays.

3. The method for inverting α-nucleus activity based on energy spectrum analysis according to claim 1, characterized in that, Energy spectrum acquisition and peak position identification are performed on the alpha nuclide to be detected, thereby locating characteristic peaks including: Energy spectrum of the alpha nuclide to be detected The characteristic peak is located using a peak-finding algorithm.

4. The method for inverting α-nucleus activity based on energy spectrum analysis according to claim 3, characterized in that, Based on the characteristic peaks, the net area of ​​the region of interest is calculated to obtain the net count of characteristic peaks, including: energy of characteristic peak Set the left and right regions of interest Calculate the net peak area count : in For channel counting, This is the estimated Compton scattering background.

5. The method for inverting α-nucleus activity based on energy spectrum analysis according to claim 4, characterized in that, Net peak area counts are calculated using either the trapezoidal background subtraction method or the polynomial fitting background method. .

6. The method for inverting α-nucleus activity based on energy spectrum analysis according to claim 3, characterized in that, The characteristic peaks were located using the Gaussian derivative method.

7. The method for inverting α-nucleus activity based on energy spectrum analysis according to claim 1, characterized in that, After performing geometric and detection efficiency corrections on the detector, the corrected detection efficiency is obtained, including: Absolute detection efficiency of the detector It is energy Heyuan-Exploration Distance The function, based on measurements from the built-in rangefinder. By calling the preset efficiency calibration curve, the corrected detection efficiency can be obtained: in This is the solid angle factor at the current distance.

8. A method for calculating the activity of α-nucleotides, characterized in that, include: The activity mode of the α nuclide to be detected is determined based on the real-time collected count rate and current value. If the activity mode is determined to be a low activity mode, the low activity mode algorithm is executed; if the activity mode is determined to be a high activity mode, the high activity mode algorithm is executed. The low and high activity mode algorithms execute the α nuclide activity inversion method based on energy spectrum analysis as described in any one of claims 1-8.

9. The method for calculating the activity of α-nucleotides according to claim 8, characterized in that, The high-activity mode algorithm includes: The ionization chamber current is calculated, and the activity is calculated based on the collected current value to obtain the activity value based on the current value. The activity value based on the current is calculated as: current value × scale factor. Output the current-based activity value.

10. The method for calculating the activity of α-nucleotides according to claim 9, characterized in that, Also includes: Before outputting the current-based activity value, the alpha nuclide to be detected is qualitatively identified.

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