A Review of Numerical Models for Predicting the Energy Deposition and Resultant Thermal Response of Humans Exposed to Electromagnetic Fields

Abstract

For humans exposed to electromagnetic (EM) radiation, the resulting thermophysiologic response is not well understood. Because it is urdikely that this information will be determined from quantitative experimentation, it is necessary to develop theoretical models which predict the resultant thermat response after exposure to EM fields. Thesecalculations are difficult and involved because the human thermoregulatory system is very complex. In this paper, the important mmrericaf models are reviewed and possibilities for future development are discussed.

Estimation of Core Temperature Elevation in Humans and Animals for Whole-Body Averaged Sar

“…The hypothalamus is located around the center of the head, and one of the main functions of the hypothalamus is to control the thermophysiological response. In (6), the coefficient of the perspiration rate associated with the temperature elevation in the hypothalamus is much larger than that for the body surface temperature [10,30]. The difference in the perspiration rate between adults and children is marginal, as has been reported in [7].…”

“…The formula proposed in [29] was applied in our model. The variations of blood perfusion in the skin through vasodilatation are expressed in terms of the temperature increase in the hypothalamus and the average temperature increase in the skin as given in [30].…”

“…Then, the perspiration rate in (3) was simplified to be zero in the rabbit. The perspiration coefficients in the humans are assumed to depend on the temperature elevation in the skin and/or hypothalamus [10,30]:…”

Thermal Therapy, Part IV: Electromagnetic and Thermal Dosimetry

“…87 The central issue concerning the dosimetric assessment of the absorption of EM energy by biological tissues is how much is absorbed and where it is deposited. 88 This is usually quantifi ed in terms of the SAR, which is the mass-normalized rate at which EM energy is absorbed by the object at a specifi c location and thus is a good predictor of thermal effects. In the context of RF or microwaves, two alternatives are used, allowing the SAR evaluation from either electric fi eld or temperature measurement.…”

“…88 Specifi c absorption rate is a useful dosimetric measurement between approximately 100 kHz and 10 GHz. At frequencies below about 100 kHz, a more useful measure of dose is often the electric fi eld strength in tissue, in units of volts per meter.…”