Examination of the sensing radius of open-ended coaxial probes in dielectric measurements of biological tissues

Abstract

A number of emerging electromagnetic diagnostic and therapeutic devices are designed based on estimates of benign and malignant tissue dielectric properties at different frequencies and temperatures. Accurate tissue dielectric measurements are crucial for the development of these technologies. Although the dielectric measurement procedure is straightforward, several factors can introduce uncertainties and errors into dielectric data. These errors or confounders can be strictly related to the acquisition system or to the intrinsic properties of the investigated tissues. Generally, uncertainties are higher in the dielectric measurement of diseased tissues, due to their heterogeneity and complex structure and composition. These confounders can be minimized by clearly defining the measurement sensing volume, and characterizing the tissue distribution within that volume. The volume is defined by sensing depth and radius. In this work, early-stage experiments are presented to investigate the sensing radius for biological heterogeneous tissues, with the aim of providing more accurate dielectric measurements to support medical device development.