Useful radiation dose biomarkers for early identification of partial-body exposures

Although less urgent than the physical injuries caused by an unexpected nuclear and radiological (NR) event, radiation damages can be treated more effectively if the intensity and extent of the exposure are evaluated rapidly. In this work, the authors followed within the first 7 d after exposure a few early biomarkers that could be easily deployable (simple and fast sampling and analysis) to determine their potential in distinguishing a total body irradiation (TBI) from a dose-equivalent partial exposure. A plausible accident scenario was created for this study by exposing unilaterally nonhuman primates of body mass comparable to humans to 5 Gy, to either the whole body or to part of it. Using logistic regression analysis, it was shown that both a combination of three parameters together [absolute neutrophil count; monocyte count on the first day; and C-reactive protein (CRP) 5 d after exposure] or CRP 7 d after irradiation completely separated the partial exposures from the TBIs. A quasi-complete separation using receiver-operator characteristic (ROC) was observed for neutrophil count to lymphocyte count ratio during the first day after exposure.