The value of reconstruction of radiation incidents

A film badge, or thermoluminescent personal dosemeter, as a means of assessing personal radiation dose is adequate under normal working exposure circumstances. However, in a radiation incident where the direction, dimensions and gradient of the radiation field may be of prime importance, the personal dosemeter does not always indicate a dose which is representative of whole body or partial body dose. Reconstruction of such an incident is therefore essential in determining these parameters. In this paper, reference will be to the need for prompt reconstruction, the value of a search interview and repeated re-enactment of the incident. It will emphasize the need for a personal dosemeter, and describe how the recorded dose may be used as a basis for substantiating both the information derived from the search interview and subsequent physical and radiation measurements. These measurements are used to predict the partial and average whole body exposures, which in turn may be compared to the assessment of radiation exposure indicated by a study of the chormosome aberration yield in human lymphocytes. The principles involved here are discussed with reference to an incident involving the over-exposure of two radiographers working in an industrial environment