The variability of dielectric permittivity of biological tissues with water content

Several experimental campaigns aimed at the dielectric characterization of healthy and malignant tissues, have been proposed over many years. However, disagreements among the results posed a number of questions on accurate knowledge of dielectric properties of biological tissues up to date. The reason for these disagreements are several. We aim to partially address these issues by firstly establishing a rigorous procedure for the measurement of ex-vivo animal and human-derived tissue samples. Then, we investigate the correlation between the dielectric data variability and sample hydration. Measurements were obtained from 0.5 to 50 GHz from liver and kidney cortex of porcine, ovine and bovine animals and one human cadaver. The correlation between the standard deviation of the measurements for each sample and its exact water content is investigated. This enabled the thorough analysis of both the intra- and inter-organ variability together with the intra- and inter-animal variability. Results show that the sample hydration level has a direct influence on the intra- and inter-organ variability, both for homogeneous animal and human tissues.