Aug 12, 2011

Head Exposure System for a Human Provocation Study to Assess the Possible Influence of UMTS-Like Electromagnetic Fields on Cerebral Blood Circulation Using Near-Infrared Imaging

Hugo Lehmann, Laurent Pollara, Sonja Spichtig, Sven Kühn, and Martin Wolf, Bioelectromagnetics, Volume 33, Issue 2, pp. 124–133, February 2012. Online August 12, 2011

A novel head exposure setup for efficient and precisely defined exposure of specific brain regions of human subjects equipped with a near-infrared imaging sensor is presented. The subjects were exposed to Universal Mobile Telecommunications System (UMTS)-like electromagnetic fields (EMF) by using a patch antenna at close distance to the head. Various regions of the head were chosen for localized exposure and simultaneous NIRI investigation. The control software enabled the simple adaptation of the test parameters during exploratory testing as well as the performance of controlled, randomized, crossover and double-blind provocation studies. A simple continuous wave signal and three different UMTS signals with carrier frequencies of 1900 MHz were chosen for the exposures with three doses: sham, low (spatial peak SAR = 0.18 W/kg averaged over 10 g) and high (spatial peak SAR = 1.8 W/kg averaged over 10 g). The SAR assessment was performed by measurement and simulation, the direct comparison of which showed good agreement in terms of spatial peak SAR and SAR distribution. In a variability analysis of the spatial peak SAR over 10 g assessed by numerical simulations showed maximal deviations of −22% and +32% from the nominal situation.

The scientific and technical impact of the study can be summarized as:

  • a novel setup for region specific exposure of the human brain to electro-magnetic fields with UMTS signals was developed
  • the setup allows simultaneous electromagnetic field exposure and near-infrared measurement at the human head
  • the setup provides low exposure uncertainty, combined with high SAR efficiency and minimal impairment of test subjects