THE USE OF BIOLOGICAL INDICATORS IN THE EVALUATION OF RADIATION INJURY IN SELECTED CASES: THE DAKAR (SENEGAL) AND FLEURUS (BELGIUM) RADIATION ACCIDENTS.

Jean Marc BERTHO, Maâmar SOUIDI, Marc BENDERITTER and Patrick GOURMELON
Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-roses, France

Abstract

The evaluation of radiation-induced damage to vital physiological systems remains difficult after an accidental irradiation, mainly because of unknown irradiation conditions (dose, dose rate, geometry of exposure). The physical dose reconstruction, the biological dosimetry and clinical symptoms are sometime insufficient to propose a robust diagnosis and/or prognosis. Thus the use of biological indicators of damage to specific physiological systems may be useful in order to delineate extent and severity of the radiation-induced damage and to help define a therapeutic strategy. We used such biological indicators to evaluate and follow the evolution of radiation-induced damage in three victims, one from the Fleurus accident (Belgium, 2006) and two from the Dakar accident (Senegal, 2006). These three victims received a mean radiation dose of 4.5 Gy, 2.3 Gy and 1 Gy, respectively. The Flt3-ligand plasma concentration was used to assess the hematopoietic system. Citrulline concentration was used as an indicator of damage to the digestive tract. Several oxysterols were measured as hepatic and vascular markers. The measurement of Flt3-ligand showed the occurrence of an hematopoietic syndrome in two of these patients and the citrulline concentration showed the absence of gastrointestinal damage. Sub-clinical damage to the liver and the cardiovascular system was evidenced by oxysterol measurements. These results were correlated with classical biochemical markers, confirming the interest in these predictive new biological indicators. Overall, the follow-up of these three patients demonstrated the value of a multi-parametric approach in the evaluation of radiation-induced damage, especially in complex accidental irradiation situations.