ID Number		761
Study Type		Engineering & Physics
Model		900, 1800 MHz (CW) exposure to pigs and analysis of brain tissue properties
Details		Pigs were anesthetised and measured for brain tissue conductivity and permitivity properties at 900 and 1800 MHz. In the living pig brain tissue, values were ~ 10-20% higher than the same continuing measurments immediately after death. Implications of this are that conductivity and permitivity properties, and thus coresponding SAR values, in might also be higher in living human brain tissue than estimations based upon measurements in non-living tissue, although since standards and measurements are all based upon values in non-living tissue, the issue is essentially relative. In subsequent studies, similar measurements were made in human brain gray matter tissue in the frequency range of 8002450 MHz at < 10 h after death. Measurements yielded a mean value for gray matter equivalent conductivity of 1.13 +/- 0.12 and 2.09 +/- 0.16 S/m at 800 and 2450 MHz, respectively. The mean value of measured relative permittivity was 58.2 +/- 3.3 and 54.7 +/- 3.3 at 800 and 2450 MHz, respectively. Assuming a positive temperature coefficient in living tissue, equivalent conductivity values in living tissue are suggested to be somewhat higher than generally accepted values based upon measurements in non-living tissues.
Findings		Not Applicable to Bioeffects
Status		Completed With Publication
Principal Investigator		Austrian Research Center, Seibersdorf - georg.neubauer@arcs.ac.at
Funding Agency		Motorola
Country		AUSTRIA
References		Schmid, G et al. Bioelectromagnetics, (2003) 24:423-430 Schmid, G et al. Bioelectromagnetics, (2003) 24:413-422
Comments		Because current compliance standards as well as human SAR determination are all based upon conductivity and permitivity values taken from deceased tissue, a relative 10-20~ increase across the board in SAR values would not change the relative relationship between SAR and compliance limits