Photon dose kernels dataset for nuclear medicine dosimetry, using the GATE Monte Carlo toolkit

Abstract

Photon dose point kernels (DPKs) were generated using the GATE toolkit for different media and for radionuclides of interest in nuclear medicine. In the present work the primary photon contribution of different isotopes in different media is calculated, since this dataset is not available in the literature according to our knowledge. The generated dataset consists of photon DPKs for some of the most commonly used radionuclides in nuclear medicine, generated for different media namely water, lung and bone. A homogenous spherical phantom was used, with a point gamma source at the center, emitting isotropically. Validation of the generated dose kernels in water was performed by comparing against the dose kernels published by Furhang et al. (1996). The kernels that were generated include the following radionuclides: Cu-64, Ga-67, Ga-68, Tc-99, Pd-103, In-111, I-123, I-124, I-125, I-131, Cs-137, Sm-153, Lu-177 and were calculated, taking into account dose at all voxels of the medium, at different distances from the point source. The scored dose in each voxel comes from the primary photons of the sources, and all the subsequent interactions that are taking place. Scoring in voxels of different sizes was performed to investigate the influence of the voxel size, taking into account measured statistical uncertainty. DPKs for different radioisotopes and media can be used in 3-D internal dosimetry, by exploiting the anatomical information of each patient (e.g. CT images). When the material of each voxel is known, dose in specific organs can be calculated, without making the assumption that body is a homogeneous material consisting of water, as it is the case in most DPKs based methods. Thus, more accurate algorithms for personalized, real time dose calculation can be implemented, as it has already been suggested in the literature.