Local SAR Prediction Errors with Variation of Electrical Properties in the Head at 7T

Muhammad Hassan Chishti¹, Zhangwei Wang², Desmond Yeo¹

The ability to accurately predict Specific Absorption Rate (SAR) is a key to patient safety during RF exposure in MR scans. SAR is highly dependent on accurate values of the tissues electrical properties. In this work, we investigate the errors in EM-modeling-based SAR prediction when incorrect electrical conductivity and relative permittivity values are applied. In the 7T human body model simulations performed, results show that the maximum deviation (from nominal) of the ratio of peak SAR10g to the whole head average SAR is -7.83% and occurs when both electrical conductivity and relative permittivity of the tissues are reduced by 20%.