Christ A, Gosselin MC, Kühn S, Kuster N. Impact of pinna compression on the RF absorption in the heads of adult and juvenile cell phone users. Bioelectromagnetics. Mar 30, 2010 Ahead of print.
The level of exposure to electromagnetic fields of the head tissues of mobile phone users depends on several parameters, and one of them is a distance between the phone and the tissue. The pinna represents a spacer between the phone and the head. Deformation of the pinna when a cell phone is pressed against the head reduces the distance between the phone and the head and may lead to an increase in exposure. Because of possible age-related differences in pinna size and elasticity, this increase may be more significant in children. Anatomical head models of adults and children developed for exposure estimation do not usually take into account pinna deformation.
The objective of this study was to assess possible age-related differences in specific absorption rate (SAR) related to deformation of the pinna in adults and children – mobile phone users.
Three anatomical head models (34-year old male, 11-year old girl and 6-year old boy) and two generic cell phone models with different antennas (monopole and integrated dual-band) were used in this study. The finite-difference time-domain (FDTD) method was used for all evaluations. A special device was developed to assess the distance between the pinna surface and the head depending on the applied force. Measurements were performed on 40 children (6-8 years of age) and 28 adults. The measurement results were then translated to the anatomical head models.
Adults and 6-8 year-old children did not differ significantly in terms of distances from the pinna surface to head tissues while holding a mobile phone. The average distances were 10.5±2.0 mm for children and 9.5 mm for adults. The numerical exposure analysis showed that the reduction in distance due to pinna compression resulted in an increase of about 2 dB in the 10 g peak spatial SAR for both children and adults.
Interpretation and Conclusion
In this study, no differences were observed between adults and children in the thickness of their compressed pinna and, consequently, in the peak spatial SAR.