Small-sized probe for local measuring electrical properties of the tissues inside of human body: design, modelling...

In this study, a new idea is suggested for designing an appropriate bio-impedance probe in the form of a biopsy forceps to measure the electrical properties of the tissues inside the body. First, by analytically solving the Laplace equation for wedge-shaped tissue in the mouth of the probe, the relationship between electric potential (results from excitation current) in a different point on the tissue and the electrical properties of the tissue is obtained. Then, to evaluate the designed bio-impedance probe using the finite element method and the experimental data obtained for different tissues by Gabriel et al., modelling and simulation at different frequencies from 50 Hz to 5 MHz were done. Finally, to evaluate the performance of the designed probe in comparison to other methods, measurements were carried out using three methods for the same tissue. Nyquist curves were drawn and electrical properties extracted for all the three methods. It was found that the designed probe results are close to the actual values with an error of <2%. The main features of the designed probe are small size and non-invasive measurement.