The US Transuranium and Uranium Registries: forty years' experience and new directions in the analysis of actinides in human tissues

The US Transuranium and Uranium Registries (USTUR) studies the distribution, biokinetics and tissue dosimetry of actinide elements through radiochemical analysis of autopsy tissues voluntarily donated by occupationally exposed persons. The paper provides an overview of the analytical methods for plutonium (Pu), americium (Am) and uranium (U) isotopic determination in human tissues currently applied at USTUR. The results of inter-comparing 239+240Pu, 241Am and 234,235,238U determinations by sector ?eld inductively coupled mass spectrometry (SF-ICP-MS), a-spectrometry (AS) and kinetic phosphorescence analysis (KPA) are discussed. SFICP-MS is a major advance over AS and KPA in enabling the measurement of the 240Pu/ 239Pu atom ratio, the short-lived ß-emitter 241Pu, and long-lived 236U. For the ?rst time, 241Am and 241Pu were measured in human tissues using SF-ICP-MS. The paper also presents a new avenue of USTUR research in the application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to elemental bio-imaging (EBI) of the actinides in human tissues