Alpha particle transport in voxelized trabecular bone images

Alpha particles are of current interest in radionuclide therapy due to their short range and high rates of energy transfer to target tissues. Published values of alpha-particle absorbed fractions in skeletal tissues do not vary with particle energy, cellularity or skeletal site. To correct for this, absorbed fractions are calculated using Monte Carlo techniques in 3D voxelized images. In this study absorbed fraction values are acquired for deep marrow (TAM), shallow marrow (TAMS), and trabecular bone volume (TBV) targets for a broad energy spectrum of alpha particles originating in the TAM, TAMs, and TBV of 33 voxelized images. Additionally the impact of marrow cellularity on absorbed fraction is investigated, by varying the fat percentage from 0% to 100% for each bone site; Calculated absorbed fractions show an energy dependence for all source-target combinations. Additionally, AF(TAM←TAM) is greatly influenced by marrow cellularity. These dependencies on energy and cellularity illustrate the weaknesses in the current ICRP methodology.*; *This dissertation is a compound document (contains both a paper copy and a CD as part of the dissertation). The CD requires the following system requirements: Adobe Acrobat