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- Title
Biodosimetry methods for analysis of complex radiation exposure scenarios.
- Authors
Bhat, Nagesh N.
- Abstract
Biodosimetry method using biological indicators of radiation is part of regulatory investigation of excess exposure, play a crucial role in medical management of exposed individuals and help to address triage needs in case of small as well as large scale radiological incidents. When either physical dosimeter becomes unreliable or not available as in most radiological incidents, biodosimetry assays help in ascertaining the exposure and quantify the dose. Complex exposure scenarios offer challenges for dose assessment. Expectations from the biological indicators are; sensitivity over wide dose range, specificity to radiation, stability over several months, retrospective analysis, ability to distinguish non-uniform exposure, minimally invasive sample collection, reproducibility of calibration factors, repeatability, quick dose estimation and amenable to automation for highthroughput analysis. Non-uniform fields, mixed radiation fields, extremity exposures, protracted exposures, chronic exposures, inter-individual variation of response and medical conditions such as leucopenia are few of the examples. To address these challenges, it has become necessary to study the response of the assays by simulating the complex exposure conditions. Besides, no single assay can effectively address all challenges. The classic Dicentric chromosome aberration (DCA) assay being highly specific to radiation, which has withstood the test of time, is considered as gold standard. This assay has few limitations such as stability of signal, may not work at high doses and highly labor intensive. Other assays such as Fluorescent in situ hybridization assay, premature chromosome condensation assay, and micronucleus assay, -H2AX assay and also many clinical dosimetry methods along with DCA as a multi-parametric approach help us to address most over-exposure scenarios. Biodosimetry lab of HS&EG, BARC has established state of the art facilities for addressing the requirements of Biodosimetry analysis and developed many indigenous facilities for achieving high-throughput analysis. Many innovative methods developed to address the various logistics of processing, preparation of slides, scoring and reporting of dose estimates. Emergency exercises were also conducted to demonstrate the claimed throughput of the lab. Statistical uncertainties, error propagation due to variation of background, calibration error and sample size were taken in to account while deciding minimum detection limit, reportable dose and upper and lower confidence of reported dose. The assays established and SoPs developed have effectively helped to address complex challenges of radiation exposure.
- Subjects
RADIATION exposure; FLUORESCENCE in situ hybridization; CHROMOSOME abnormalities; BIOINDICATORS; EXPOSURE dose
- Publication
Nitte University Journal of Health Science, 2018, p60
- ISSN
2249-7110
- Publication type
Article