Naylor G P, Haines J W, Whysall K, Bonas H E, Harrison J D
National Radiological Protection Board, Chilton, Didcot, Oxon, UK.
Sci Total Environ. 1993 Mar 25;130-131:429-35. doi: 10.1016/0048-9697(93)90097-p.
In order to set limits on environmental and occupational intakes of radionuclides, information is needed on their uptake and metabolism in man. Human data are very limited, particularly for long-lived alpha-emitting isotopes such as those of the actinides. Animal experiments are therefore an important source of data on the distribution of radionuclides in tissues, and the effects of factors such as subject age and the chemical form of elements on gastrointestinal absorption. The NRPB performs experimental programs using mainly rats and guinea pigs. In order to study the gastrointestinal absorption and tissue distribution of plutonium, americium and polonium, a variety of analytical techniques are employed. These include ion exchange and solvent extraction leading to alpha spectrometry and liquid scintillation counting. The investigation of low specific-activity environmental or industrial materials, and the very low bioavailability of elements such as the actinides, means that very low levels of activity have to be measured. Contamination at the dissection and tissue separation stage, as well as during the radiochemistry, has to be rigorously avoided. Where very detailed information is needed on the location of radionuclides within tissues, such as in the study of alpha-emitter distribution in the intestine, autoradiography is used. The application and relevance of different measurement techniques to animal studies will be discussed and examples of the results presented.
为了对放射性核素的环境和职业摄入量设定限值，需要了解它们在人体中的摄取和代谢情况。人体数据非常有限，尤其是对于长寿命的发射α粒子的同位素，如锕系元素的同位素。因此，动物实验是获取放射性核素在组织中分布数据以及诸如受试者年龄和元素化学形态等因素对胃肠道吸收影响数据的重要来源。国家辐射防护委员会主要使用大鼠和豚鼠开展实验项目。为了研究钚、镅和钋的胃肠道吸收及组织分布，采用了多种分析技术。这些技术包括离子交换和溶剂萃取，随后进行α能谱分析和液体闪烁计数。对低比活度环境或工业材料的研究以及锕系元素等元素的极低生物利用度意味着必须测量极低水平的活度。在解剖和组织分离阶段以及放射化学过程中，必须严格避免污染。当需要关于放射性核素在组织内位置的非常详细的信息时，例如在研究肠道中发射α粒子的物质分布时，会使用放射自显影技术。将讨论不同测量技术在动物研究中的应用及相关性，并给出结果示例。
