Tissue Thickness Effects on Radiometric Internal Body Temperature Measurements

This paper presents a study of the impact of tissue layer thicknesses on subcutaneous temperature measurements using microwave radiometry. A near-field antenna (NFA) is designed to receive black-body radiation from the brain when placed on top of six tissue layers of a human forehead. Each layer has a weighted contribution to the thermal noise power received by the NFA. In this paper, reciprocity is applied to computationally determine the weights of each layer which are needed to estimate the temperature. These weights depend on the tissue layer conductivities and thicknesses. The variation of tissue thicknesses between different body types result in different weights which affect the temperature measurement. It is found in simulations that for example maximizing skull thickness, results in an estimated temperature error of 0.82%.