An Efficient 3D RF Simulation Tool for Dielectric Shimming Optimization

Abstract

High permittivity materials, in the form of “dielectric pads” are used in neuroimaging and body applications to improve B1+ homogeneity and intensity or to reduce corresponding SAR measures. In 3D, systematic pad design is computationally intensive with very long associated simulation times. We propose a hybrid solution to this problem by combining the flexibility of FDTD to model complex background configurations (coil/shield/subject) with an integral equation approach that takes the presence of a dielectric pad into account. This solution leads to speed up factors of 30 – 40 compared with conventional FDTD approaches and enables effective 3D dielectric pad design.