SAR assessment using tissues Homogenization Technique

This paper presents a new approach which allows reducing the computation time as well as the memory requirement. Dealing with SAR assessment the resolution often used nowadays is the millimetre resolution of Magnetic Resonance Imaging (MRI) techniques. Such resolution complies with the numerical constraints up to 5GHz but requires large memory and induces important computation time. Using homogenized tissues and larger grid for the electric field calculation and non homogenized tissues for the conductivity and density the Specific Absorption Rate (SAR) can by estimated with a limited reduction of accuracy. This Tissues Homogenization Technique (THT) has been analyzed with a 1D multilayer structure exposed to a plane wave and to a dipole operated at 900MHz and applied to a 3D child head model exposed to a plane wave. This THT approach allows relaxing the constraints on the grid size of simulations performed with the finite difference in time domain with a limited impact on the accuracy of simulations.