Biological dosimetry is an internationally recognized method for quantifying and estimating radiation dose following suspected or verified excessive exposure to ionising radiation. In severe radiation accidents where a large number of people are potentially affected, it is possible to distinguish irradiated from non-irradiated people in order to initiate appropriate medical care if necessary. In addition to severe incidents caused by technical failure, environmental disasters, military actions, or criminal abuse, there are also radiation accidents in which only one or a few individuals are affected in the frame of occupational or medical exposure. The requirements for biological dosimetry are fundamentally different for these two scenarios. In particular, for large-scale radiation accidents, pre-screening methods are necessary to increase the throughput of samples for a rough first-dose categorization. The rapid development and increasing use of omics methods in research as well as in individual applications provides new opportunities for biological dosimetry. In addition to the discovery and search for new biomarkers, dosimetry assays based on omics technologies are becoming increasingly interesting and hold great potential, especially for large-scale dosimetry. In the following review, the different areas of biological dosimetry, the problems in finding suitable biomarkers, the current status of biomarker research based on omics, the potential applications of assays using omics technologies, and also the limitations for the different areas of biological dosimetry are discussed.

This chapter describes situations where individuals may be potentially exposed to ionizing radiation in accidental, occupational, or public exposures excluding those from clinical radiotherapy. Each exposure type can have very specific characteristics ranging in radiation quality, dose, dose rate, length of exposures, and proportion of the body acute exposure. As such, some long-term health effects of low-dose exposures are described including effects on the embryo and fetus, heritable diseases, cataracts, and cardiovascular effects. Special focus on exposure to radon is included along with the health effects specific to this exposure situation. Accidental and malicious exposures can also include high-dose scenarios that can lead to the development of acute radiation syndrome (ARS). Details of ARS are described along with how it can be diagnosed. In some exposure scenarios, large numbers of individuals are exposed such that triage is required to quickly identify those needing medical intervention to mitigate ARS. Strategies for triage for treatment are described with respect to trauma, contamination, and exposure along with a discussion of suggested countermeasures for internal exposure and medical follow-up after exposure. In order to assist with determining the dose of radiation an individual has been exposed to, several biodosimetry techniques are described. The final section focuses on the radiation protection system including definitions of quantities commonly used and the limits of exposure.