Biological speciation in the field of internal dosimetry

Speciation studies consist in the determination of the molecular characteristics of the elements. The research currently carried out in that field is aimed at describing the intracellular deposit of the radionuclides and the complexation mechanisms which determine their behaviour. Such studies are developed in order to contribute towards the solution of two major problems in the field of internal dosimetry: the realistic assessment of the dose received by the target cells and the therapeutic removal of neptunium or uranium after internal contamination. The work presented thereafter resumes the main results obtained in that field. (authors)