The Future of Radiological Protection


InterDosi-Based Monte-Carlo Assessment of S-Values on a Voxel-Based Crab Phantom for Cs-137, Te-132 and Co-58

Author(s): Hafssa BenDriss 1, EL Mahjoub Chakir 1, Jaafar EL Bakkali 2, Abderrahim Doudouh 2
( 1 Ibn Tofail University, Kenitra, Morocco; 2 Nuclear Medicine department, Military Hospital Mohammed V, Rabat, Morocco)


In order to assess internal doses absorbed by an organism exposed to ionizing radiation, the MIRD organization had defined, through its schema, a key coefficient known as S-value. In this work, we have used InterDosi code to estimate S-values on a voxel-based crab phantom, which illustrates the best marine ionizing radiation pollution-indicator. In this context, three radioisotopes mainly presented in a wastewater released by nuclear power activities, namely Cs-137, Te-132 and Co-58, were taken into consideration to calculate S-values in the five main organs of a crab, namely: heart, hepatopancreas, gills, gonads and shell. InterDosi simulations have been run on 64 CPUs of the HPC-MARWAN-CNRST computing grid, each one runs 108 for uncharged particles and 1/10 of this value for charged particles. The S-value calculation has been simplified by not calculating the Specific Absorbed Fraction (SAF) for an energy E1 if it is previously calculated for an energy E0 in a condition that (E1/E0<=1.01). This simplification was applied in order to speed up the simulation as the number of SAFs required is too big. Results had shown that the Te-132 produces the most higher S-values on the crab, followed by Cs-137 and Co-58. It can be explained by the fact that the Te-132 is the most high-energy beta- emitter among the three radioisotopes. We concluded that radiological impact of crab exposure to radioactive wastewater is radio-isotope dependent. The calculation of S-values for all radio-isotopes presented in a radioactive wastewater is required for internal dose assessment.

Keywords: InterDosi; S-value; Monte-Carlo; Internal dosimetry; aquatic radiation protection