Calculation of Temperature Rise Induced by Cellular Phones in the Human Head

Abstract

The problem associated with the calculation of tem- perature rise induced by cellular phones in the human head tak- ing into account the effects of the thermoregulatory system (TS) is discussed in this work. The formulation uses the finite dif fer- ence time domain method. The inclusion of the TS considered three modifications in the bioheat equation, which was solve d dynamically: first, the convective heat transfer coefficien t as a function of the gradient between the skin temperature and the environment temperature; second, the skin blood flow rate as a function of the energy absorved by the skin and by the brain; and third, the temperature in the brain constant at 36.8 o C. The bioheat equation was solved for a 3D anatomically based model of the human head composed of 15 tissues. The cellular phone was modeled as a half-wavelength dipole irradiating at 1.8GHz with a power of 120mW. The inclusion of the TS resulted in a maximum temperature rise of 0.029 o C in the skin, a value con- siderably smaller than previously reported. These results sug- gest that modern cellular phones operating at full power would produce temperature rise in the human head within the basal temperature of these tissues.