Cytogenetic Biodosimetry in Radiation Emergency Medicine: 5. The Dicentric Chromosome and its Role in Biodosimetry

Abstract

In the case of nuclear or radiological emergencies, biodosimetry has been used to estimate radiation dose to exposed persons and provide information to physicians for clinical treatment and counselling of possible future stochastic consequences. There are currently several biological endpoints and techniques available for assessing partial or whole-body radiological exposure in peripheral blood lymphocytes. However, the use of dicentric chromosomes (Dic) in biodosimetry is still recognized as the main dose-assessment method for estimating exposure to ionizing radiation and has become a routine component of radiation protection. Dics are specific to radiation exposure and the background level is low in non-exposed individuals, making them advantageous in biodosimetry. Here, we provide a review of Dics and its role in biodosimetry as research efforts on assay optimization and high throughput have been published since the mid-1960s. Additionally, we provide recommended technical information (e.g., colcemid addition, scoring, generating doseresponse curves) needed to implement the dicentric chromosome assay (DCA) in laboratories and to allow comparable dose assessment following exposure to acute ionizing radiation. While DCA has been optimized for nuclear or radiological emergencies, increased uncertainty in dose estimation can be caused by the scoring of Dic and variation of calibration curves. Total dose, doserate, radiation quality, and sampling time after exposure are some of the factors that influence the results of DCA. Future consideration is also needed as no single assay is sufficient for all radiation scenarios.