ID Number		539
Study Type		Engineering & Physics
Model		900, 1800 MHz (GSM) exposure and modeling of temperature increases in the human brain
Details		Human head computational model (from MRI images) was analyzed for temperature increases during theoretical RF exposure from 900 MHz and 1800 MHz GSM cellular telephones with anterior-posterior as well as lateral irradiation. At the maximal peak SAR (10 W/kg), temperature increases in the brain were calculated at between 0.39 and 1.64 degrees, depending upon the position of the antenna. The authors comment that “… more extensive examination of the temperature profile shows that at no point does the absolute temperature in the brain exceed 38.1 degrees C in any of the cases considered …” and “…this study seems to confirm that such exposure is unlikely to cause the temperature in the brain to rise by more than about 1 deg C above the normal body core temperature ...". No thermoregulatory mechanisms were considered in the model, and thus calculated temperature increases would likely be lower in actual practice. In a follow-on study using a model of the human eye, RF exposures at 380, 900, and 1800 MHz at 10 W/kg (ICNIRP limit for peak occupational exposure), assuming a distance of 24 mm, and consideration of an equivalent blood flow, the authors report maximal temperature increases within the lens of 1.4 degrees C.
Findings		Not Applicable to Bioeffects
Status		Completed With Publication
Principal Investigator		NRPB, UK
Funding Agency		HPA (NRPB), UK
Country		UNITED KINGDOM
References		Wainwright, PR Phys Med Biol, (2007) 52:3335-3350 Wainwright, P Phys. Med. Biol., (2000) 45:2363-2372
Comments		Similar results were obtained by Van Leeuwen (333), Wainwright (539), Wang (723), and Bernardi (763).In the NRPB document 4 (5) 1993 after a discussion of biological effects, paragraph 81 concludes "It is concluded that localised temperatures up to about 38 deg C in the head and the developing fetus (including embryo), 39 deg C in the neck and trunk, and 40 deg C in the extremities are unlikely to produce adverse effects. Localised temperatures are unlikely to exceed these values if maximum local SARs in the head and in the fetus averaged over any 10 g mass are less than 10 W/kg, maximum local SARs in the neck and trunk averaged over any 100 g mass are less than 10W/kg, and maximum SARs in the limbs averaged over any 100 g mass are less than 2 W/kg."