Establishment and validation of a calibration curve for dicentric chromosome induced by 6MV X-ray.

This article focuses on establishing and validating a dose–response calibration curve for the dicentric chromosome assay (DCA) at the biodosimetry laboratory of Mashhad University of Medical Sciences in northeast Iran. The DCA, considered the gold standard in biological dosimetry, quantifies radiation-induced chromosomal damage by correlating radiation dose with the frequency of dicentric chromosomes in peripheral blood lymphocytes. Using 6 MV X-rays from a linear accelerator, blood samples from healthy volunteers were irradiated at doses ranging from 0 to 5 Gray, cultured, and analyzed following International Atomic Energy Agency protocols. The resulting calibration curve, fitted with a linear-quadratic model, showed strong correlation with existing studies and was validated by accurately estimating doses of blind samples. This calibration curve enables the laboratory to estimate radiation exposure doses in accidental or occupational settings, supporting emergency response and public health decision-making.