Kramer G H, Hauck B M, Allen S A
Human Monitoring Laboratory, Radiation Protection Bureau, Ottawa Ontario, Canada.
Health Phys. 1998 May;74(5):594-601. doi: 10.1097/00004032-199805000-00007.
The Human Monitoring Laboratory has compared the LLNL and JAERI torso phantoms using its germanium detector lung counting system by measuring the counting efficiencies for radioactive materials in the phantoms at photon energies of 17.7 keV, 59.5 keV, 121.8 keV, and 344 keV to assess the similarity (or differences) in performance characteristics. The counting efficiencies obtained from the two phantoms were compared by converting the Chest Wall Thickness data and Adipose Mass Fractions of the phantoms to Muscle Equivalent Chest Wall Thicknesses. The counting efficiencies for the two phantoms were found to be within a factor of 1.44 of each other at 17.7 keV, 1.30 at 59.5 keV, 1.25 at 121.8 keV, and 1.17 at 344 keV when using a four detector array (JAERI efficiency divided by LLNL efficiency). However, individual detector responses show that the counting efficiencies from the two phantoms differ considerably in the region of the heart (up to a factor of 6 at 17 keV). Other areas above the lungs give counting efficiencies that are similar to each other. A routine intercomparison exercise with Cameco Corporation has shown that the counting efficiencies derived from the LLNL and JAERI phantoms were found to be within a factor of 1.18 (JAERI/LLNL) when a natural uranium lung set was used to calibrate a lung counter consisting of phoswich detectors. This work has also shown that over the energy range 63 keV-185 keV the LLNL phantom can be used to calibrate phoswich detector systems that are positioned on the back of the subject.
人体监测实验室使用其锗探测器肺部计数系统，通过测量17.7 keV、59.5 keV、121.8 keV和344 keV光子能量下模型中放射性物质的计数效率，对劳伦斯利弗莫尔国家实验室（LLNL）和日本原子能研究所（JAERI）的躯干模型进行了比较，以评估性能特征的相似性（或差异）。通过将模型的胸壁厚度数据和脂肪质量分数转换为肌肉等效胸壁厚度，比较了从这两个模型获得的计数效率。当使用四探测器阵列时（JAERI效率除以LLNL效率），发现这两个模型在17.7 keV时的计数效率相差1.44倍以内，在59.5 keV时相差1.30倍，在121.8 keV时相差1.25倍，在344 keV时相差1.17倍。然而，单个探测器的响应表明，这两个模型在心脏区域的计数效率差异很大（在17 keV时相差高达6倍）。肺部上方的其他区域的计数效率彼此相似。与卡梅科公司进行的常规比对实验表明，当使用天然铀肺部装置校准由磷光体探测器组成的肺部计数器时，从LLNL和JAERI模型得出的计数效率相差1.18倍（JAERI/LLNL）。这项工作还表明，在63 keV - 185 keV的能量范围内，LLNL模型可用于校准位于受试者背部的磷光体探测器系统。
