Empirical validation of SAR values predicted by FDTD modeling*†

Abstract

Rapid increase in the use of numerical techniques to predict current density or specific absorption rate (SAR) in sophisticated three dimensional anatomical computer models of man and animals has resulted in the need to understand how numerical solutions of the complex electrodynamics equations match with empirical measurements. This aspect is particularly important because different numerical codes and computer models are used in research settings as a guide in designing clinical devices, telecommunication systems, and safety standards. To ensure compliance with safety guidelines during equipment design, manufacturing and maintenance, realistic and accurate models could be used as a bridge between empirical data and actual exposure conditions. Before these tools are transitioned into the hands of health safety officers and system designers, their accuracy and limitations must be verified under a variety of exposure conditions using available analytical and empirical dosimetry techniques. In this paper, empirical validation of SAR values predicted by finite difference time domain (FDTD) numerical code on sphere and rat is presented. The results of this study show a good agreement between empirical and theoretical methods and, thus, offer a relatively high confidence in SAR predictions obtained from digital anatomical models based on the FDTD numerical code.

Effects of averaging procedures for electrical properties at the interface of dissimilar tissues in the human head with finite-difference time-domain modelling

“…Initially, the different averaging methods were applied to a homogeneous sphere of muscle illuminated by a plane wave at 2.06GHz [33]. The relative permittivity of the sphere was 55.57 and the conductivity was 2.25S/m.…”

Specific Absorption Rate Analysis of Heterogeneous Head Models with EEG Electrodes/Leads at 7T MRI

“…However, the use of an anatomically finegrained head model may add potential errors when modeling the internal structures of the head [Gajsek 2002]. Due to the difficulties in matching exactly all the anatomical definitions to existing literature, some of the anatomical structures were assigned the same electrical properties; 16 different electrical properties were used to characterize the anatomical structures (Figure 2).…”

Electromagnetic and thermal characterization of an UHF‐applicator for concurrent irradiation and high resolution non‐perturbing optical microscopy of cells

“…Second, a method for making point SAR measurements in cell layer only a few micrometers thick has yet to be discovered. Third, and finally, computational approaches such as the FDTD method have evolved to such levels of confidence and sophistication that they are becoming widely accepted in non-ionizing radiation dosimetry [e.g., Gaj sek et al, 2002].…”