Abstract
The biokinetic model for systemic americium (Am) currently recommended by the International Commission on Radiological Protection (ICRP) for application to occupational intake of Am is based on information available through the early 1990s. Much additional information on Am biokinetics has been developed in the past 25 y, including measurements of retention and excretion of 241Am in many workers with 241Am burdens and post mortem measurements of 241Am in tissues of some of those workers. The ICRP’s current Am model is reasonably consistent with the updated information, with the main exception that there is some evidence that the current model may overestimate the rate of excretion of systemic Am at late times. This paper provides an overview of current information on the systemic kinetics of Am in adult human subjects and laboratory animals and presents an updated biokinetic model for systemic Am that addresses the discrepancies between the current database and current ICRP systemic model for Am.
