Nagaoka T, Watanabe S. (2009). Estimation of variability of specific absorption rate with physical description of children exposed to electromagnetic field in the VHF band. Conf Proc IEEE Eng Med Biol Soc. 1:942-945.
According to the International Commission on Non-Ionizing radiation Protection (ICNIRP) and the Institute of Electrical and Electronics Engineers (IEEE) guidelines, safety of exposure to radiofrequency (RF) electromagnetic fields is evaluated in terms of specific absorption rate (SAR). SAR is not directly measurable; it can be estimated by numerical methods using voxel-based models of humans. Though individuals, even of the same age, have different physical features (height, weight and body shape), most of the human voxel models are average models of adults or children, and studies on SAR variations due to differences in physical features are scares.
The aim of the study was to estimate variability of SAR in humans based on three-dimensional body shape data from actual three-year old children.
The subjects were 30 Japanese children (14 boys and 16 girls). The body shape data in the standing position were obtained using a three-dimensional surface laser scanner. The SARs of the models of three-year old children were calculated for exposure to vertically polarized EMFs in a very high frequency band (30 MHz-300 MHz) using the finite-difference time-domain method.
Results, Interpretation and Conclusion
It was found that variations in the whole-body averaged SAR at the whole-body resonant frequency (~150 MHz) were smaller than at other frequencies. The range of the whole-body averaged SAR at the whole-body resonant frequency that covered ~95% of 3-year old children was ±13%. Individual variability in SAR for people of other age groups should be estimated because variability in physical features is different at different ages.