人体甲状腺中^(131)I活度测量的计量标准器研制

Development of a Metrological Standard Device for Measuring ^(131)I Activity in Human Thyroid

为解决防护至诊疗量级人体甲状腺中^(131)I活度的直接测量问题,以及人体甲状腺中^(131)I活度测量相关仪器的量值溯源问题,研制了便携式现场计量标准器。结合IAEA/ANSI颈部模体开展了标准器的探测效率校准和活度定值方法研究,通过实验测量和模拟计算确定了不同探测距离下的效率曲线,建立了人体甲状腺中^(131)I活度的量值溯源方法。标准器在贴近颈部直接测量时长为600s时,最小可探测活度达到4.67 Bq;对用于开展人体甲状腺中^(131)I活度测量的便携式γ能谱仪进行了校准,典型的相对扩展不确定度为5.5%(k=2)。该标准器的研制为职业健康监测、核应急以及甲状腺诊疗中^(131)I的准确测量和量值保障建立了关键设备基础。

To solve the problem of direct ^(131)I activity measurement in human thyroid for radiological protection and diagnosis and treatment in nuclear medicine,and the problem of traceability of related instruments for ^(131)I activity measurement in human thyroid,a portable on-site radioactivity measurement metrological standard device was developed.In combination with the IAEA/ANSI neck phantom,the detection efficiency calibration and activity determination methods of the standardization were studied.Through experimental measurement and simulation calculation,the efficiency curve at different detection distances was determined,and the traceability method of ^(131)I activity in the human thyroid was established.The minimum detectable activity reached 4.67 Bq when the standard was directly measured close to the neck for 600s;the portable gamma spectrometer used to measure the activity of ^(131)I in the human thyroid was calibrated with the relative expanded uncertainty of 5.5%(k=2).The development of this standard has established a key equipment foundation for the accurate measurement and traceability of ^(131)I activity in occupational health monitoring,nuclear emergency,and diagnosis and treatment of thyroid diseases.