Overview of biodosimetry for management of unplanned exposures to ionizing radiation

Biodosimetry has the potential to provide the information needed from individuals to respond to unplanned exposures to ionizing radiation in a way that enables the medical response system to function effectively. Four types of circumstances are considered: (1) triage for large scale events, (2) medical management of ARS following a large scale event, (3) medical management of small scale events, and (4) assessment of long-term risks. There are two different but potentially complementary types of biodosimetry: those based on an individual’s biological responses or on physical phenomena. Because of the different nature of these types of biodosimetry, they have different strengths and limitations that, if considered carefully, lead to their appropriate use in specified circumstances. The biologically based parameters have the possible clinical advantage of reflecting the biological consequences of the radiation. However, their limitations include that the responses potentially may be confounded by: (1) inherent differences in the response to damage in individuals; (2) prior or concurrent pathophysiologically-based processes; and (3) changes over time in an individual’s response to radiation after the exposure. The physically-based parameters are less likely to be perturbed by these factors but have the potential limitations that they measure only the dose at the body location measured, and cannot reflect the biological implications of responding to the dose. Based on the respective strengths and weaknesses of biologically based and physically-based biodosimetry, we suggest that, for exposures to large numbers of people, the physically-based parameters may be especially useful for initial triage, while the biologically based parameters may be especially useful for guiding acute and long-term treatment. For exposures involving small numbers of people, biodosimetry is likely to have a secondary role. For determination of long-term effects of radiation, biodosimetry is likely to remain the principal method for assessing dose–response relationships.