Room: Exhibit Hall | Forum 1
Purpose: Practical dosimetry is often done using anthropomorphic phantoms, which are constructed using the materials with atomic number and the density similar to human tissue. However the existing phantoms do not take into account the distinction between bones and bone marrow. The purpose of this study is to investigate the effect of this simplification on bone marrow, and bone dosimetry by simulation of voxelized phantoms using GATE Monte Carlo code.
Methods: Pelvis-abdomen CT images of a 5-year-old child were used to create the voxelized phantom using GATE Monte Carlo code. Finally, the three-dimensional dose distribution inside the phantom was obtained when the phantom is exposed to mono-energetic photons of 40 keV. The simulations were repeated again by replacing the bone marrow tissue of the voxelized phantom with bone. The difference in bone marrow dose of the two simulations were obtained.
Results: The results of this study show that there is a large error (more than 80%) in bone marrow dose, if it is replaced by bone tissue for construction of phantoms.
Conclusion: According to the results of this study, not considering the bone marrow in constructing anthropomorphic phantoms, will introduce a large error in dose measurements in low energy photon fields.