Application of cytogenetic techniques in complex scenarios of exposure to ionizing radiation

Biological dosimetry is used to estimate the absorbed dose through biomarkers. These markers were developed primarily to estimate uniform whole-body exposure. However, accidental exposures usually occur as partial-body or prolonged exposure with low dose rate. This study used an approach focusing on biological effect of low LET radiation by cytogenetic assays to apply in complex scenarios of ionizing radiation exposure. The methodologies of unstable alterations and micronuclei were used following the manual of IAEA. The u, D, L, Z, CR, Qdr, Dolphin and Bayesian tests were used for dose estimation in cases of partial-body exposure; and the ANOVA and Tukey test for prolonged exposure with low dose rate. The dicentric's chromosome proves to be the most specific biomarker for dose estimation in both whole-body and complex exposure scenarios. The micronuclei also presented positive behavior for these scenarios, although this type of biomarker tends to have a greater interindividual variation. The findings reaffirm the necessity of establishing the dose rate involved in exposure scenario, because this factor is important for the correct dose estimation. Therefore, the determination of which assay to be used and the dose rate involved are imprescriptible for any biological dosimetry study. (author)