The use of the dicentric assay for biological dosimetry for radiation accidents in bulgaria

This paper details the construction of a ¹³⁷Cs gamma calibration curve that has been established for dicentric assay and the testing and validation of the curve through biological dosimetry in three situations of suspected workplace overexposure that arose accidentally or through negligence or lack of appropriate safety measures. The three situations were: (1) suspected ¹³⁷Cs contamination in a factory air supply; (2) suspected exposure to an industrial ¹⁹²Ir source; and (3) accidental exposure of construction workers to radiation from a ⁶⁰Co radiotherapy source in a hospital medical physics department. From a total of 24 potentially-exposed subjects, only one worker was found to have a statistically significant dose (0.16 Gy, 95% confidence intervals 0.02-0.43 Gy). In all other cases, the main function of the biological dosimetry was to reassure the subjects that any dose received was low.