Challenges in the Dielectric Measurement of Heterogeneous Tissues: Impact of Uncertainty in Sensing Depth Calculation

The dielectric properties of biological tissues are parameters used in the design and development of microwave medical technologies. For example, knowledge of these properties is key in hyperthermia treatment planning, which has promise for improving outcomes in the treatment of cancer. In this study, we examine a source of error that can impact the accuracy of dielectric measurements, especially those of heterogeneous tissues. Specifically, we consider the determination of the sensing depth of the dielectric probe. As measurement uncertainty can be used as a threshold to define the sensing depth, we here investigate the impact of the measurement uncertainty on the resulting sensing depth value. This work demonstrates that the calculated sensing depth value can vary significantly with the magnitude of the uncertainty. Further, the results suggest that it is prudent to carefully measure the uncertainty value for each specific measurement scenario. With a better understanding of the calculated sensing depth of the probe under various circumstances, improved estimates of tissue properties can be obtained to support developing medical technologies.