Review of methods to measure internal contamination in an emergency.

In the event of a radiation emergency, people close to the site of the incident may be exposed to radiation by external exposure, or as a result of intakes of radioactive material. For these incidents it may be necessary to monitor members of the public both for external and internal contamination. This work reviews currently available equipment for the assessment of internal exposure following an emergency. It concentrates on incidents involving the spread of radioactive material and on contamination by radionuclides which emit penetrating radiation. It is essential that this monitoring is carried out as soon as possible so that people who have been exposed at a level which could have an effect on health can be identified and receive prompt medical assessment. Proposed action levels to identify people who need medical attention are reviewed to determine the required sensitivity of monitoring equipment. For releases containing gamma-ray emitting radionuclides the best means of measuring internal contamination is to use detectors placed close to the body (whole body or partial body monitoring). Laboratory based whole body monitors could be used but these may well be inconveniently located and so equipment which can be deployed to the site of an incident has been developed and these are described. The need for rapid selection and prioritisation of people for monitoring, methods to deal with potentially high numbers of contaminated people and the requirement for a means of rapidly interpreting monitoring information are also discussed.It has been found that for many types of incidents and scenarios, systems based on unshielded high-resolution detectors and hand-held instruments do have the required sensitivity to identify people who require medical assessment.