Stannard J N
Department of Radiation Biology and Biophysics, University of Rochester School of Medicine and Dentistry, New York 14642, USA.
Health Phys. 2003 Sep;85(3):264-73; discussion 273-4. doi: 10.1097/00004032-200309000-00003.
The concepts of critical organ or tissue and the calculation of radiation dose have been and may well continue to be central to the development of standards for most radionuclides. In the case of plutonium the occupational standard was based on a modification of the direct calculations of maximum permissible annual dose (MPAD) or dose rate but critical organs must still be chosen for different routes of entry and different compounds and for all of the derived standards. Changes in such standards by likely variations in metabolic parameters and models are shown to be significant but not large. Application of the critical organ concept to population exposure standards poses some new problems because the basic MPAD does not distinguish among organs. A simple scaling factor from occupational exposure standards thus is not satisfactory. Use of the concept of dose commitment has many advantages but it is still necessary to select a critical organ and calculate dose. By-passing some of the problems in present practices by using risk-estimates seems unlikely for plutonium at the present time because of the paucity of human effects data and the fact that the animal experiments used quite different dosage regimens from the likely exposure situations to plutonium. A brief comparison is made of radiation and chemical hazard evaluation procedures.
关键器官或组织的概念以及辐射剂量的计算一直是且很可能继续是大多数放射性核素标准制定的核心。就钚而言，职业标准是基于对最大允许年剂量（MPAD）或剂量率直接计算的修正，但仍必须针对不同的摄入途径、不同的化合物以及所有派生标准选择关键器官。代谢参数和模型的可能变化导致此类标准的变化被证明是显著的，但幅度不大。将关键器官概念应用于人群暴露标准会带来一些新问题，因为基本的MPAD并未区分不同器官。因此，简单地从职业暴露标准进行比例缩放并不令人满意。使用剂量承诺概念有许多优点，但仍需选择关键器官并计算剂量。由于人类效应数据匮乏，且动物实验所采用的剂量方案与钚的可能暴露情况有很大不同，目前似乎不太可能通过使用风险估计来规避当前实践中的一些问题。本文对辐射和化学危害评估程序进行了简要比较。
