Biological Dosimetry by the Triage Dicentric Chromosome Assay: Potential Implications for Treatment of Acute Radiation Syndrome in Radiological Mass Casualties

TLDR

Biological dosimetry, especially the dicentric chromosome assay, is essential for estimating radiation dose. The study aims to increase throughput of the dicentric chromosome assay for mass‑casualty incidents by evaluating how reducing metaphase spreads affects dose‑prediction accuracy and its usefulness for acute radiation syndrome triage. The authors analyzed data from a double‑blinded interlaboratory comparison of five cytogenetic biodosimetry laboratories, truncating metaphase spread analysis to 50 or fewer spreads and employing a large scorer network to assess dose‑prediction accuracy. The results showed that even with as few as 50 metaphases, laboratories’ dose predictions were in good agreement and adequate for guiding acute radiation syndrome diagnosis and treatment, demonstrating that a biodosimetry network can rapidly triage patients.

Abstract

Biological dosimetry is an essential tool for estimating radiation dose. The dicentric chromosome assay (DCA) is currently the tool of choice. Because the assay is labor-intensive and time-consuming, strategies are needed to increase throughput for use in radiation mass casualty incidents. One such strategy is to truncate metaphase spread analysis for triage dose estimates by scoring 50 or fewer metaphases, compared to a routine analysis of 500 to 1000 metaphases, and to increase throughput using a large group of scorers in a biodosimetry network. Previously, the National Institutes for Allergies and Infectious Diseases (NIAID) and the Armed Forces Radiobiology Research Institute (AFRRI) sponsored a double-blinded interlaboratory comparison among five established international cytogenetic biodosimetry laboratories to determine the variability in calibration curves and in dose measurements in unknown, irradiated samples. In the present study, we further analyzed the published data from this previous study to investigate how the number of metaphase spreads influences dose prediction accuracy and how this information could be of value in the triage and management of people at risk for the acute radiation syndrome (ARS). Although, as expected, accuracy decreased with lower numbers of metaphase spreads analyzed, predicted doses by the laboratories were in good agreement and were judged to be adequate to guide diagnosis and treatment of ARS. These results demonstrate that for rapid triage, a network of cytogenetic biodosimetry laboratories can accurately assess doses even with a lower number of scored metaphases.