Comparison of computational phantoms and investigation of the effect of biodistribution on activity estimations

A comparison was made between two computational phantoms, modelled from the unified phantom UPh-08 T, for whole-body counting applications. One of these was further compared with the International Commission on Radiological Protection reference adult male computational phantom. The simulations that were performed for the comparison of all three voxel phantoms use various distributions of Co-60. The two voxel phantoms of the UPh-08 T showed good agreement, despite different methods of phantom modelling. Also, effects on efficiency of the inhomogeneous distribution of a radionuclide in the computational UPh-08 T phantom were studied, using the realistic biodistribution of La-140. The results show that the activity estimation of radionuclides, which are inhomogeneously distributed in the human body, will be in error if a homogeneous distribution is assumed for the calibration of whole-body counting systems.