Calculation of energy absorption in a human body model in a homogeneous pulsed high-frequency field

Abstract

The purpose of this work was to estimate whether a considerable thermal absorption appears in the human body during standardized 1.5 T magnetic resonance imaging (MRI) system procedures applied in medical diagnostics. Therefore, based on magnetic resonance (MR) scans of a male volunteer, a human body heterogeneous tissue model has been simulated by a finite element method using isoparametric formulation, verified before with measurements. Numerical calculation has been performed for two radiofrequency (RF) exposure systems: saddle-shaped coils and bird-cage coil. Energy deposition in terms of specific absorption, specific absorption rate (SAR) and temperature elevation in the model has been calculated for the `worst-case' imaging sequence, i.e., multislice turbo spin echo sequence. Comparison to existing recommendations shows that there is no thermal hazard at 64 MHz, corresponding to 1.5 T MRI systems. However, new simulations should be performed for MR systems operating at higher frequencies.