Skeletal contribution in lung measurements for the in vivo assessment of Am-241

摘要

Physical phantoms used for the calibration of in vivo measurement equipments represent an approximate geometry of the body and usually contain a uniform distribution of radionuclides in the organ of interest. Numerical voxel phantoms allow an improvement of the calibration method by means of a more realistic definition of the phantom and the source. The distribution of the activity in the tissues evolves with time and it can be estimated by solving the specific biokinetic model of the radionuclide. Those results of predicted activity retained in the compartments of the model can be translated into the organs of a voxel phantom to be used as the source of radiation for a Monte Carlo radiation transport code. In this way, different patterns of contamination, according to different times after the intake, can be modelled and appropriate detection efficiencies can be obtained. In particular, it is studied the influence of the skeletal contribution in lung measurements in the in vivo assessment of Am-241.