Fast SAR Estimation Via a Hybrid Approach

Shumin Wang¹, Jeff H. Duyn¹

Estimation of local specific absorption rate (SAR) is a major challenge in high-field (>3.0 Tesla) multi-channel transmission systems. Conventional Finite-Difference Time-Domain (FDTD) method is often found inefficient to give subject-specific results. Recent studies sped up the process by applying Amperes law to obtain electrical field distributions via measured transverse B1 fields. The drawback is that only the longitudinal electrical fields can be calculated, which may yield large discrepancy. We present a fast numerical approach by calculating all three components of magnetic field by an integral-equation method and obtain the electric fields by Amperes law subsequently. Combined with fast subject modeling, this method may provide a viable approach for subject-specific SAR estimations.