Analysis of RF exposure in the head tissues of children and adults

TLDR

Comparisons of RF exposure are limited by small data sets and require confirmation. The study analyzes RF exposure in children’s head tissues at 900–2400 MHz using cellular handsets and dipole sources. MRI‑derived heterogeneous head models were used to compute SAR over 10 g and 1 g in children and adults, with morphing techniques applied to assess age‑class variability. Simulations show that while maximum SAR over 10 g is similar between adults and children, children aged 5–8 yr exhibit about twice the SAR over 1 g in peripheral brain tissues, a difference not seen in older children, likely due to thinner pinna, skin, and skull.

Abstract

This paper analyzes the radio frequencies (RF) exposure in the head tissues of children using a cellular handset or RF sources (a dipole and a generic handset) at 900, 1800, 2100 and 2400 MHz. Based on magnetic resonance imaging, child head models have been developed. The maximum specific absorption rate (SAR) over 10 g in the head has been analyzed in seven child and six adult heterogeneous head models. The influence of the variability in the same age class is carried out using models based on a morphing technique. The SAR over 1 g in specific tissues has also been assessed in the different types of child and adult head models. Comparisons are performed but nevertheless need to be confirmed since they have been derived from data sets of limited size. The simulations that have been performed show that the differences between the maximum SAR over 10 g estimated in the head models of the adults and the ones of the children are small compared to the standard deviations. But they indicate that the maximum SAR in 1 g of peripheral brain tissues of the child models aged between 5 and 8 years is about two times higher than in adult models. This difference is not observed for the child models of children above 8 years old: the maximum SAR in 1 g of peripheral brain tissues is about the same as the one in adult models. Such differences can be explained by the lower thicknesses of pinna, skin and skull of the younger child models.