3 Biodosimetry

The interaction of ionizing radiation with biological systems results in a wide range of responses at the cellular and molecular levels. Using biodosimetry approaches, quantification of these responses can be used to estimate the dose of radiation an individual has received. In the context of radiation triage, a dose estimate serves as a surrogate of potential radiological injury. As biodosimetry techniques incorporate measurements of the actual individual biological response to radiation, biodosimetry may provide more accurate indicators of the potential extent of injury compared with physical dosimetry methods. It is not yet known, however, how closely the various biodosimetry approaches reflect individual injury or predict individual risk, so the current applications of biodosimetry are for the prediction of dose only. Biodosimetry techniques have been previously described in ICRU Report 68. This document aims to provide an up-todate description of biodosimetry methods, introducing newer methods [premature chromosome condensation (PCC), γH2AX, emerging “-omics” technologies] but not including methods no longer used (somatic mutations). The descriptions of some mature methodologies [dicentric chromosome assay (DCA), cytokinesis-block micronucleus (CBMN) assay, translocation analysis by fluorescence in-situ hybridization (FISH)] will overlap with those found in ICRU Report 68 but will also cover updated developments and are included herein to provide a sufficiently comprehensive description of biodosimetry to form a standalone document. A number of characteristics contribute toward the usefulness of biodosimetry and determine the situations in which a particular method will be the most useful. A biodosimeter should be considered regarding the following: