Strategy for Population Triage Based on Dicentric Analysis

TLDR

Large‑scale accidental ionizing‑radiation exposure requires rapid triage by scoring dicentrics and ring chromosomes in 50 metaphases, followed by dose estimation from 500 metaphases. The study proposes software for automatic dicentric scoring, tested on victims of a Dakar accident, to improve triage and dose estimation. The method involved manual scoring of 50 and 500 metaphases and applying the software for automatic scoring of dicentrics. Automatic scoring misclassified only 4.35% of cases, compared to 50% with manual 50‑metaphase scoring, and matched the accuracy of manual 500‑metaphase scoring while being faster, making it suitable for triage and individual dose estimation.

Abstract

After large-scale accidental overexposure to ionizing radiation, a rapid triage of the exposed population can be performed by scoring dicentrics and ring chromosomes among 50 metaphases. This is rapid but is not accurate because the sensitivity is around 0.5 Gy. After the triage step, dose can be estimated by scoring 500 metaphases. This is lengthy but very accurate because the sensitivity is between 0.1 and 0.2 Gy. To improve the methodology, we propose the use of software for automatic dicentric scoring that was tested on victims of an accident in Dakar. Manual scoring of 50 metaphases was carried out, then manual scoring of 500 metaphases, and automatic scoring. Comparison between the dose classifications obtained with manual scoring on 50 metaphases and 500 metaphases showed 50% misclassification with the manual scoring on 50 metaphases. Comparison between the dose classifications obtained with the automatic scoring and manual scoring on 500 metaphases showed only 4.35% misclassification with the automatic scoring. The automatic scoring method is more accurate than the manual scoring on 50 metaphases and can therefore be used for triage, and in place of the manual scoring on 500 metaphases method for individual dose estimation, because it is as accurate and much faster.