Exploring the Safety Margin in Current Guidelines for Electromagnetic Exposure

Abstract

Exposure to radio-frequency (RF) electromagnetic fields (EMF) is unavoidable in today's modern life. This exposure is growing mainly because of rapid growth in telecommunication systems. Awareness of the possible risks of exposure to EMF has raised public concern. To avoid any potential adverse health effect, international organizations of ICNIRP and IEEE have developed basic restrictions (BRs) on specific absorption rate (SAR) for human exposure to RF EMF. These restrictions were derived based on limited data, i.e. experimental assessments (almost entirely) in animals or dose assessment using generic phantoms (approximated human anatomy). In order to account for uncertainties in the data and to provide a sufficient level of safety, the limits are lowered by large safety factors which were selected based on expert opinion rather than a rigorous quantitative process. The safety factors are not quantified for various exposure scenarios. In view of the lack of knowledge on the incorporated safety factor, and in the light of unique opportunity that medical applications can provide to establish dose-response relationship for humans, the aim of this thesis is to explore the relevance of the current BRs for functional tissue changes and to tailor SAR limits for localized exposure above which tissue damage takes place. This thesis, by means of advanced simulation tools, shows that the current restrictions on local exposure to RF EMF are conservative and should be more refined based on accurate dosimetry and useful data on experimental assessments in humans