Numerical simulation of SAR and Si-field inhomogeneity of shielded rf coils loaded with the human head

Abstract

The finite-difference time-domain (FDTD) method is combined with the method of moments (MoM) to compute the electromagnetic fields of shielded radio-frequency (RF) coils loaded with an anatomically accurate model of a human head for high-frequency magnetic resonance imaging (MRI) applications. The combined method can predict both the specific energy absorption rate (SAR) and the magnetic field (known as the B\ field) excited by any RF coils. Results for SAR and BI field distribution, excited by shielded and end-capped birdcage coils, are calculated at 64, 128, 171, and 256 MHz. The results show that the value of SAR increases when the frequency of the B\ field increases and the B\ field exhibits a strong inhomogeneity at high frequencies. © 1998 IEEE.