Yoder C, Balter S, Boice J D, Grogan H, Mumma M, Rothenberg L N, Passmore C, Vetter R J, Dauer L T
Landauer, Inc. Retired, Glenwood, IL, United States of America.
Columbia University, New York, NY, United States of America.
J Radiol Prot. 2021 Feb 26;41(1). doi: 10.1088/1361-6498/abcfcb.
The study of low dose and low-dose rate exposure is of central importance in understanding the possible range of health effects from prolonged exposures to radiation. The One Million Person Study of Radiation Workers and Veterans (MPS) of low-dose health effects was designed to evaluate radiation risks among healthy American workers and veterans. The MPS is evaluating low-dose and dose-rate effects, intakes of radioactive elements, cancer and non-cancer outcomes, as well as differences in risks between women and men. Medical radiation workers make up a large group of individuals occupationally exposed to low doses of radiation from external x-ray/gamma exposures. For the MPS, about 100 000 United States medical radiation workers have been selected for study. The approach to the complex dosimetry circumstances for such workers over three to four decades of occupation were initially and broadly described in National Council on Radiation Protection and Measurements (NCRP) Report No. 178. NCRP Commentary No. 30 provides more detail and describes an optimum approach for using personal monitoring data to estimate lung and other organ doses applicable to the cohort and provides specific precautions/considerations applicable to the dosimetry of medical radiation worker organ doses for use in epidemiologic studies. The use of protective aprons creates dosimetric complexity. It is recommended that dose values from dosimeters worn over a protective apron be reduced by a factor of 20 for estimating mean organ doses to tissues located in the torso and that 15% of the marrow should be assumed to remain unshielded for exposure scenarios when aprons are worn. Conversion coefficients relating personal dose equivalent,(10) in mSv, to mean absorbed doses to organs and tissues,in mGy, for females and males for six exposure scenarios have been determined and presented for use in the MPS. This Memorandum summarises several key points in NCRP Commentary No. 30.
低剂量和低剂量率照射的研究对于理解长期暴露于辐射可能产生的健康影响范围至关重要。百万辐射工作者和退伍军人低剂量健康影响研究（MPS）旨在评估美国健康工作者和退伍军人中的辐射风险。MPS正在评估低剂量和剂量率效应、放射性元素摄入量、癌症和非癌症结局，以及男女之间的风险差异。医学辐射工作者构成了因职业暴露于外部X射线/γ射线低剂量辐射的一大群体。对于MPS，已选择约10万名美国医学辐射工作者进行研究。国家辐射防护与测量委员会（NCRP）第178号报告最初广泛描述了此类工作者在三到四十年职业生涯中复杂剂量测定情况的处理方法。NCRP第30号评论提供了更多细节，并描述了使用个人监测数据估计适用于该队列的肺部和其他器官剂量的最佳方法，以及适用于医学辐射工作者器官剂量剂量测定用于流行病学研究的具体预防措施/注意事项。防护围裙的使用带来了剂量测定的复杂性。建议将佩戴在防护围裙上的剂量计的剂量值降低20倍，以估计躯干中组织的平均器官剂量，并且在佩戴围裙的暴露场景中，应假定15%的骨髓仍未受到屏蔽。已确定并给出了六种暴露场景下女性和男性个人剂量当量（10）（单位为mSv）与器官和组织平均吸收剂量（单位为mGy）之间的转换系数，供MPS使用。本备忘录总结了NCRP第30号评论中的几个要点。
