Determining the influence of adult skin thickness on compliance with radiofrequency exposure limits

Abstract

It is difficult to compare studies regarding energy absorption in humans from various radiofrequency (RF) sources due to the contradictions and inconsistencies in RF dosimetry literature. Assumptions used in Specific Absorption Rate (SAR) studies have been insufficiently explored, particularly with regard to the effect of natural variation in the human population of potentially key parameters such as morphology, internal tissue and bone thicknesses and location, dielectric parameters of tissues and overall size. Due to the nature of available computational models based on either complex realistic models or the simple single tissue models this issue is not easily explored since the identified parameters are not easily varied within the models. To overcome this deficiency, we have proposed an alternative compromise model which includes a reduced set of tissues in a semi-homogeneous, simplified geometry for which the key parameters may be varied parametrically. We have reviewed some of the available data which we have used to populate the new model, and have begun to investigate which of these assumptions are appropriate; what approximation can be used in physical and computational modeling of humans for SAR calculations; and what tradeoffs can be made between accuracy and modeling requirements for practical considerations. Key issues being investigated are how SAR varies between children and adults, between males and females, and how to model SAR in the fetus of pregnant females. It is hoped that this study will produce a model and methods which allow for faster, more accurate and more efficient assessment of compliance with radiofrequency exposure limits. We have previously completed work on the effect of cranial thickness, and here we present initial results pertaining to the effects of skin thickness on SAR