Transmission of time varying magnetic field through body tissue

Abstract

Based on the principles of interaction of electromagnetic waves with semi-infinite media, a simplified model is developed for the study of biological tissue — EM wave interaction problems. The four common types of biological tissues viz, bone, blood, alveolar and muscle tissue, each in turn has been considered. Expression for the transmission loss of the incident EM waves have been derived and numerically evaluated. The results indicate that there is a frequency dependence of the transmission loss and variations with tissue type exist and that losses become significant above 30 MHz. Attenuation for muscular tissue is maximum at frequencies of about 200 MHz whereas the corresponding frequency for lung tissue is nearly the double.

Suitable experiments have been designed and performed to verify the salient results of the model and a fair degree of agreement has been found between the experimental results and theoretical predictions. Possibilities for the improvement of the model and future applications of the model have been outlined.