以原級標準量測技術量測放射性核種活度之研究

The study of radionuclide activity measurement using primary standard technique

袁明程(Ming-Chen Yuan)

指導教授 ： 王竹方

國立清華大學/原子科學院/生醫工程與環境科學系/博士(2010年)

https://doi.org/10.6843/NTHU.2010.00241

摘要

In this research we established a radionuclide activity absolute counting system which can be the primary standard of the calibration chain for radionuclide activity measurement area in Taiwan. The counting system was composed of a 4π proportional counter, two NaI(Tl) detectors, NIM modules and a personal computer. The proportional counter and the NaI(Tl) detectors respectively detect the charged particles and photons and work with coincidence. That allows researchers to measure the radionuclide activity only by the counts of the counting system and do not need any standard sources. The performance of the counting system was verified by international comparisons and showed that the measurement result of the counting system is equivalent with the Key Comparison Reference Value. The primary standard system was applied to nuclear medicine area and radioactive waste clearance measurement area in this research. In nuclear medicine area, the activity of two radiopharmaceuticals, 67Ga and 188Re, were standardized by the counting system. The standardized radioactive solution of the two nuclides with the standard uncertainties smaller than 0.5% was introduced to calibrate the 4πγ ionization chambers of National Radiation Standard Laboratory, and the Capintec-CRC15R radionuclide activity calibrator which was popularly used in hospitals and radiopharmacies to enhance the accuracy of activity dose received by patients. In radioactive waste clearance measurement area, the standard drums, the calibration techniques of radioactive waste drum counting system and the correction methods of the primal measurement data of the drum counting systems were developed and applied to the proficiency testing study. These techniques improved the proficiency testing pass rate of participants from 20% (primal result of participants) to 70% (corrected result of participants). Details of the primary standard system, the associated techniques and results are described in this report.

關鍵字

放射核種活度 ； 原級標準 ； 4πβ-γ符合計測 ； 絕對計測 ； 校正 ； 能力試驗 ； 錸-188 ； 鎵-67

並列摘要

本研究建立放射源活度的絕對量測系統，可作為國內放射源活度量測校正鏈之原級標準。此量測系統是由一支4 π比例計數器、2支碘化鈉偵檢器、核儀模組及一部個人電腦所組成，放射源的活度可由此量測系統的計數值直接導出，而無須藉助其他的標準放射源。本量測系統參與多次的國際量測比對活動，其量測結果皆與國際比對參考值達到等同程度，確證了本量測系統的整體性能。在本研究中將此原級標準系統應用於核子醫學領域與放射性廢棄物解除管制量測領域，在核子醫學領域中，本報告以此系統建立67Ga與188Re放射性藥物的放射活度原級標準，其量測不確定度小於0.5％，此活度標準藉由經量測系統標準化後的放射性藥物，傳遞至國家游離輻射標準實驗室所屬的4πγ游離腔與一般醫院及製藥中心常用的Capintec-CRC 15R放射核種校正器上，用以增進病患接受放射性藥物活度劑量的準確度。在放射性廢棄物解除管制量測領域，本研究建立標準校正桶與放射性廢料桶量測儀器的校正技術與數據修正方法，並且將這些技術與方法應用於放射性廢棄物解除管制量測能力試驗的研究上，由能力試驗的結果分析，本研究所建立技術與方法，可將能力試驗參與者的通過率由20％ 提升至70％。關於本研究建立的原級標準量測系統及相關的技術與方法將詳述於本報告中。

並列關鍵字

Radionuclide activity ； Primary standard ； 4πβ-γ coincidence counting ； Absolute counting ； Calibration ； Proficiency testing ； Re-188 ； Ga-67

參考文獻

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