Computational Dosimetry of the Human Head Exposed to Near-Field Microwaves Using Measured Blood Flow

Computational human thermal modeling studies have suffered from lack of reliable data regarding tissue blood flow. In this study, we report the measured results of blood flow on the surface of the head at multiple sites in human subjects (12 healthy young male subjects, 22-24 years), using a laser Doppler blood-flow method. We then incorporate these measured blood flow in a computational bioheat thermal model in anatomical human head models and investigate the effects of individual variations in blood flow on a microwave-induced temperature elevation in the frequency range from 1 to 12 GHz. The measurements show variations in blood flow at different sites and depths from the skin surface. However, computational bioheat modeling indicates that the typical variability of peak temperature elevation in the head due to individual and regional variations in the blood flow is less than ±15%. The presented data will aid in the development of more accurate and consistent human thermal models and strengthen the thermophysiological rationale of guidelines and standards for human radio-frequency near-field exposure.