Marsh J W, Birchall A, Butterweck G, Dorrian M D, Huet C, Ortega X, Reineking A, Tymen G, Schuler Ch, Vargas A, Vezzu G, Wendt J
National Radiological Protection Board, Didcot, Oxon, UK.
Radiat Prot Dosimetry. 2002;102(3):229-48. doi: 10.1093/oxfordjournals.rpd.a006092.
A parameter uncertainty analysis has been performed to derive the probability distribution of the weighted equivalent dose to lung for an adult (w(lung) H(lung)) per unit exposure to radon progeny in the home. The analysis was performed using the ICRP Publication 66 human respiratory tract model (HRTM) with tissue weighting factor for the lung, w(lung) = 0.12 and the radiation weighting factor for alpha particles, wR = 20. It is assumed that the HRTM is a realistic representation of the physical and biological processes, and that the parameter values are uncertain. The parameter probability distributions used in the analysis were based on a combination of experimental results and expert judgement from several prominent European scientists. The assignment of the probability distributions describing the uncertainty in the values of the assigned fractions (ABB, Abb, AAI) of the tissue weighting factor proved difficult in practice due to lack of quantitative data. Because of this several distributions were considered. The results of the analysis give a mean value of w(lung) H(lung) per unit exposure to radon progeny in the home of 15 mSv per working level month (WLM) for a population. For a given radon gas concentration, the mean value of w(lung) H(lung) per unit exposure is 13 mSv per 200 Bq.m(-3).y of 222Rn. Parameters characterising the distributions of w(lung) H(lung) per unit exposure are given. If the ICRP weighting factors are fixed at their default values (ABB, Abb, AAI = 0.333, 0.333, 0.333; w(lung) = 0.12; and wr = 20) then on the basis of this uncertainty analysis it is extremely unlikely (P approximately 0.0007) that a value of Hw/Pp for exposure in the home is as low as 4 mSv per WLM, the value determined with the epidemiological approach. Even when the uncertainties in the ABB, Abb, AAI, values are included then this probability is predicted to be between 0.01 to 0.08 depending upon the distribution assumed for describing the uncertainties in the ABB, Abb, AAI, values. Thus, it is concluded that the uncertainties in the HRTM parameters considered in this study cannot totally account for the discrepancy between the dosimetric and epidemiological approaches.
已进行参数不确定性分析，以得出家庭中每单位氡子体暴露量下成人肺部加权等效剂量（w(lung) H(lung)）的概率分布。该分析使用了国际辐射防护委员会第66号出版物中的人类呼吸道模型（HRTM），肺部组织权重因子w(lung) = 0.12，α粒子辐射权重因子wR = 20。假定HRTM能真实反映物理和生物过程，且参数值存在不确定性。分析中使用的参数概率分布基于若干欧洲著名科学家的实验结果和专家判断。由于缺乏定量数据，在实践中为描述组织权重因子分配分数（ABB、Abb、AAI）值的不确定性而指定概率分布颇具难度。因此考虑了几种分布。分析结果表明，对于人群而言，家庭中每单位氡子体暴露量下w(lung) H(lung)的平均值为每工作水平月（WLM）15 mSv。对于给定的氡气浓度，每单位暴露量下w(lung) H(lung)的平均值为每200 Bq·m⁻³·y的²²²Rn为13 mSv。给出了表征每单位暴露量下w(lung) H(lung)分布的参数。如果将国际辐射防护委员会的权重因子固定在其默认值（ABB、Abb、AAI = 0.333、0.333、0.333；w(lung) = 0.12；且wr = 20），那么基于此不确定性分析，家庭暴露情况下Hw/Pp值低至每WLM 4 mSv（通过流行病学方法确定的值）的可能性极小（P约为0.0007）。即便将ABB、Abb、AAI值的不确定性考虑在内，根据为描述ABB、Abb、AAI值的不确定性而假定的分布，该概率预计在0.01至0.08之间。因此得出结论，本研究中考虑的HRTM参数不确定性无法完全解释剂量学方法与流行病学方法之间的差异。
