New route in TRIPOLI-4 for radiation dosimetry calculations using ICRP 100 voxel phantoms

The TRIPOLI-4 Monte Carlo radiation transport code has been widely used in the radiation shielding, criticality safety and fission reactor physics fields to support French nuclear energy research and engineering projects. With the growing interest in using the TRIPOLI-4 code for radiation protection, radiation dosimetry, and medical application fields, the radiation dose calculations in organ-tissue level are in progress. Computational human phantoms are available from the International Commission on Radiological Protection (ICRP) report 110. These voxel phantoms have been modeled with TRIPOLI-4 using its lattice geometry options. In this study, a new route has been developed in TRIPOLI-4 and its graphical tool T4G in order to simplify the usage of voxel phantoms. An effort was made in the new route to optimize the lattice practice in modeling and to improve the particle tracking efficiency for voxel phantoms. The interactive T4G could thus display iteratively in a fast way to verify the voxel source and target organs on materials and positions. A brief analysis of current voxel-phantom irradiation scenarios for organ dose calculations was presented. Verification and validation study of this new route was conducted. Various application cases were investigated using external and internal radiation sources including typical nuclides ⁶⁰Co, ^99mTc, ¹⁸F, ¹³¹I, and ¹⁶N. (authors)