Study of the tissue volume for spatial-peak mass-averaged SAR evaluation

For being adaptable to the irregular shape of a biological model and for not underestimating the spatial-peak mass-averaged specific absorption rates (SARs) of hand-held wireless telephones, a method of taking a contiguous tissue volume for the SAR-averaging-mass is proposed. The proposed method is to obtain a tissue volume for SAR averaging by summing node masses of the layers enclosing the point in which the averaged SAR is wanted in a body model until the summed mass is closest to the required mass. Therefore, at the skin layer and in the tissue region around the sinuses such as nasal cavities, the averaging volume can follow closely the shape of the region. To investigate the effect of this algorithm on SAR evaluation, SARs have been evaluated numerically for an anatomical head with a simple hand models exposed to a mobile phone, using the proposed method and the previous method of averaging over a cubic tissue volume and the results are compared. The results show that the proposed algorithm is very reasonable and leads to more stable values for spatial-peak mass-averaged SAR evaluation in an irregularly shaped model such as a realistic human model.