| || Standardisation and Validation of Cytogenetic Markers to Quantify Radiation Absorbed Dose
Author : Venkatachalam, P.;Paul, Solomon F.D.;Kaur, Harpreet;Jeevanram, R.K.
Source : Defence Science Journal ; Vol:61(2) ; 2011 ; pp 125-132
Subject : 535.374 Radiation Hazards
Keywords : Dicentric chromosomes;micronucleus;translocations;biological dosimetry;biomarkers
Abstract : The amounts of radiation exposure received by radiation workers are monitored generally by physical dosimeters like thermoluminescence dosimeter (TLD) and film badge. However, in practice the over-exposure recorded by physical dosimeters need to be confirmed with biological dosimeters. In addition to confirming the dose recorded by physical dosimeters, biological dosimeters play an important role in estimating the doses received during accidental exposures. Exposure to high levels of radiation induces certain biochemical, biophysical, and immunological changes (biomarkers) in a cell. Measurement of these changes are generally precise but cannot be effectively used to assess the dose, as the level of these changes return to normalcy within hours to months after exposure. Thus, among various biological indicators, cytogenetic indicators are considered practical and reliable for dose estimation. The paper highlights the importance and establishment of biodosimetry facility using genetic markers such as the sensitive dicentric chromosomes, rapid micronucleus assay and stable translocations measured using fluorescence in situ hybridisation and GTG banding for retrospective dose estimation. Finally, the development of gH2AX assay, as a potential marker of triage dosimeter, is discussed.