Interlaboratory Comparison of the Dicentric Chromosome Assay for a Mixed Gamma-Neutron Radiation Field.

In the event of a criticality accident, there is a risk of high-dose exposure for affected individuals from a mixed gamma-neutron radiation field. Dosimetry in such cases is complex and requires multiple approaches. Biodosimetry methods, especially the dicentric chromosome assay (DCA), the most established method, can significantly support triage and medical care decisions after a criticality incident. However, large-scale events need collaboration between laboratories to enable timely dose assessments using DCA. We conducted a comparison among three biodosimetry laboratories, focusing on DCA-based estimates of the total dose, including the specific gamma-ray dose and neutron-heavy-particle dose for blood samples irradiated in a mixed gamma-neutron field. Although each laboratory used dose-effect curves derived from different radiation spectra and irradiation facilities, the dose estimates were acceptable, with relative deviations no greater than 21%. Overall, the study showed that collaborating between labs is feasible for individual dose estimation after a criticality accident.