EURADOS intercomparison on measurements and Monte Carlo modelling for the assessment of americium in a USTUR leg phantom

United States Transuranium and Uranium Registries (USTUR) Case 0102 was the first whole-body donation to the USTUR (1979), of a worker affected by a substantial accidental 241Am intake(1). Half of this man’s skeleton, encased in tissue-quivalent plastic, provides a unique human ‘phantom’ for calibrating in vivo counting systems. In this case, the 241Am skeletal activity was measured 25 y after the intake. Approximately 82 % of the 241Am remaining in the body was found in the bones and teeth. The241Am activity concentration throughout the skeleton (in all types of bone) was fairly uniform(2). A protocol has been proposed by a group of in vivo laboratories from Europe [CIEMAT-Spain, IRSN-France and Helmholtz Zentrum Mu¨nchen (HMGU)-Germany] and Canada (HML) participating in this DOS/USTUR intercomparison. The focus areas for the study included: (1) the efficiency pattern along the leg phantom using Germanium detectors (experimental and computational), (2) the comparison of Monte Carlo (MC) results with experimental values in counting efficiency data and (3) the inflence of americium distribution in the bone material (volume or surface).