The U.S. Transuranium Registry report on the 241Am content of a whole body. Part III: Gamma-ray measurements.

The 241Am measurements on the donor's body, followed by an analysis of each bone of the skeleton, have provided the best available calibration factors for measuring the 241Am content in the skeletons of the living. These calibration factors have already been useful in measuring the skeletal burden of several workers in the nuclear industry. This study has shown that differential linear scanning provides good results on the content of various parts of the skeleton. Previously used methods of head or leg counting for estimating total skeletal content of 241Am were also found to provide good results. These studies confirm previous recommendations that in-vivo measurement of the skull probably provides the best estimate of 241Am in the skeleton; however, other positions such as the knee are also found to be bilaterally symmetrical for identical bones on the right and left sides of the body. A comparison of measurements on the donor's body with those of other people with skeletal burdens of 241Am shows that differences in skeletal distribution do exist and are probably due to the age of the person, the duration of the skeletal 241Am burden,and perhaps the physical activity of the person. Additional measurements and studies are planned on the remaining half of the skeleton and they should further improve the accuracy of in-vivo measurements of 241Am in the human skeleton.