Quantitative Relationship between Whole Body Averaged SARs and Voxel SARs in Numerical Human Models of Pregnant Woman and 3-years Child for Far-Field Exposure

Abstract

Safety standards and guidelines for radio-frequency exposure are being set based on whole-body averaged SARs (WBA-SARs) and localized average SARs. In Japan, the WBA-SAR and 1g localized average SAR are set at 0.4W/kg and at 8W/kg, respectively, except for the arms and legs and surface of body. The safety limits of WBA-SARs were determined from observing the behavior destruction of animals for radio-frequency exposure, but those of localized average SARs were determined under the assumption that a spatial peak SAR value does not exceed 20-fold WBA-SARs without their biological evidences. In this paper, to confirm whether or not the above assumption is valid, we calculated WBA-SARs and voxel SARs in the frequency range from 50MHz to 2GHz in anatomical-based human numerical models for pregnant woman and 3-years child for vertically and horizontally polarized far-field exposures, and derived the histogram and cumulative relative frequency of voxel SARs to obtain the quantitative relationship between WBA-SARs and voxel SARs. As a result, we found that 99.90-percentile voxel SARs are not exceeding 20-fold WBA-SARs, while 99.00-percentile voxel SARs are smaller than 10-fold WBA-SARs in both human models.