New biological indicators to evaluate and monitor radiation-induced damage: an accident case report

On March 11th, 2006, a radiation accident occurred in an industrial radiation facility, in the city of Fleurus (Belgium). An operator entered an irradiation room without noticing that the cobalt-60 source (activity of 3x104 TBq) was out of the security position. Few hours after the exposure, the victim had nausea and vomiting, but these clinical signs were confounded with a benign gastroenteritis. Eighteen days later, the patient consulted for persistent nausea and headache, transitory and refractory diarrhoea and hair loss. The occurrence of a radiation accident was then proposed as an explanation for these symptoms, and the patient was taken in charge by the medical staff of Percy hospital (Clamart, France). Cytogenetic dosimetry was used to define the radiation dose and heterogeneity received by the victim. This cytogenetic analysis indicated a mean radiation dose of 4.5 Gy, based upon dicentric chromosome frequency, reciprocal translocations and total translocations. However, the presence of 18.8% of cells without dicentric chromosomes suggested of an heterogeneous irradiation. This was confirmed by the physical dosimetry, which suggested an anterior-posterior gradient of dose. The patient was then followed by the mean of several new biological indicators of radiation-induced damages to specific organs and physiological systems. The blood Flt3 ligand concentration was used to evaluate and follow the hematopoietic syndrome. Initial measurement gave