Whole-body-averaged SAR from 50 MHz to 4 GHz in the University of Florida child voxel phantoms

Abstract

The University of Florida (UF) Series B paediatric phantoms were developed for medical and radiation protection photon dosimetry. The series includes a 9 month male, a 4 year female, an 8 year female, an 11 year male and a 14 year male. In this paper they have been adapted to calculate the whole-body-averaged specific energy absorption rate (SAR) in children for plane wave exposure from 50 MHz to 4 GHz. The consideration of children is important in the application of the ICNIRP public exposure reference levels above approximately 1 GHz. The uniformly scaled models of NORMAN and NAOMI suggest that the ICNIRP reference level does not provide a conservative estimate of the whole-body-averaged SAR restriction for 5 year and 1 year old models. Comparison is made with the previous linearly scaled versions of NORMAN and NAOMI for calculations at 2 mm resolution. Further FDTD calculations were performed at resolutions of 1 and 0.7 mm above 900 MHz to elucidate the effects of grid resolution on SAR. A comparison is made between the calculated external electric fields required to produce the basic restriction on the whole-body-averaged SAR and the ICNIRP reference levels for public exposure.