Photon Beam Transport in a Voxelized Human Phantom Model: Discrete Ordinates Vs Monte Carlo

With recent development of new methods such as intensity modulated radiation therapy (IMRT) for radiation delivery, dose fields can, in principle, be generated in near-conformal three-dimensional (3-D) distributions around a designated treatment volume, while minimizing exposure to vital organs. Because the intended dose distributions are sensitive to the assumed treatment geometry, the new delivery methods demand accurate dose calculations, particularly to reduce the considerable uncertainties like those associated with body cavity inhomogeneities and surface curvatures. Although much effort has been devoted to developing Monte Carlo codes for external beam therapy, the codes have not been widely implemented into clinical use because of long computing times and often the lack of a completed validation protocol. Rigorous and computationally more efficient deterministic methodologies are desired. To this end, comparative photon-only deterministic transport calculations The American Nuclear Society's 14th Biennial Topical Meeting of the Radiation Protection and Shielding Division