The cytokinesis-blocked micronucleus assay: dose estimation and inter-individual differences in the response to...

Biological dosimetry plays an important role in case of a radiation accident or incident, either when it is the only way to estimate the dose or when it is used to complement physical dosimetry. A cytogenetic study was conducted in a group of 16 Portuguese individuals by use of the cytokinesis-blocked micronucleus (CBMN) assay. A dose-response curve for micronuclei yield was established with a linear-quadratic model: Y=(0.0122±0.0010)+(0.0241±0.0023)D+(0.0193±0.0007)D(2). Also, baseline values for the micronucleus formation in the 16 donors were analyzed, with results in close agreement with those from other laboratories. A validation experiment was carried out with three individuals. The real and the estimated doses obtained with the dose-response curve were in very good agreement, allowing the use of the micronucleus dose-response calibration curve in biological dosimetry for estimation of radiation dose in case of overexposure. The results obtained for the cytogenetic endpoints, studied in the same group of 16 individuals, were also analyzed as a function of age and gender. A higher inter-variability was observed for the higher dose points and differences in response were identified between genders, above 2Gy, for all endpoints.