To avoid potentially adverse health effects of electromagnetic fields (EMF), the International Commission on Non-Ionizing Radiation Protection (ICNIRP) has defined EMF reference levels. Restrictions on induced whole-body-averaged specific absorption rate (SAR wb) are provided to keep the whole-body temperature increase (T body, incr) under 1 °C during 30 min. Additional restrictions on the peak 10 g spatial-averaged SAR (SAR 10g) are provided to prevent excessive localized tissue heating. The objective of this study is to assess the localized peak temperature increase (T incr, max) in children upon exposure at the reference levels. Finite-difference time-domain modeling was used to calculate T incr, max in six children and two adults exposed to orthogonal plane-wave configurations. We performed a sensitivity study and Monte Carlo analysis to assess the uncertainty of the results. Considering the uncertainties in the model parameters, we found that a peak temperature increase as high as 1 °C can occur for worst-case scenarios at the ICNIRP reference levels. Since the guidelines are deduced from temperature increase, we used T incr, max as being a better metric to prevent excessive localized tissue heating instead of localized peak SAR. However, we note that the exposure time should also be considered in future guidelines. Hence, we advise defining limits on T incr, max for specified durations of exposure.

dx.doi.org/10.1088/0031-9155/56/15/020, hdl.handle.net/1765/68109
Physics in Medicine and Biology
Department of Radiation Oncology

Bakker, J, Paulides, M.M, Neufeld, E, Christ, A, Kuster, N, & van Rhoon, G.C. (2011). Children and adults exposed to electromagnetic fields at the ICNIRP reference levels: Theoretical assessment of the induced peak temperature increase. Physics in Medicine and Biology, 56(15), 4967–4989. doi:10.1088/0031-9155/56/15/020