Electrical Impedance Spectroscopy of Prostate as an Alternative Tool for Cancer Detection

The biophysical mechanisms influencing the electrical properties of tissues is a complex interplay between tissue morphology, cellular phenotypes, cell wall integrity, intra- and extra-cellular ionic concentrations, pH, temperature, and velocity in fluids, among others.

Some of these features dominate the underlying electrical properties and are able to provide significant contrast between tissue types or pathologies. Electrical impedance spectroscopy of tissue is a technology in which small alternating currents are injected between pairs of electrodes in contact with a tissue specimen. Voltages are recorded from the same pair or another pair of electrodes. The voltage-to-current ratio defines the electrical impedance of the tissue. By recording this impedance over a range of alternating current signal frequencies, we can generate a spectrum of impedance properties. Interestingly, benign and malignant tissues have vastly different appearances microscopically, which give rise to significantly different electrical impedance spectra. We have been exploring the impedance contrast available for use in prostate cancer detection and have demonstrated a number of significant contrasts. Based on these findings, our group has been developing a number of potential clinical applications to take advantage of this contrast.

Primary types of tissue found in prostate
Primary types of tissue found in prostate: An H & E stained micrograph of tissue taken from a human prostate, with vastly different morphologies present for the different tissue types. Pink regions represent extracellular spaces, purple regions represents epithelial cells or gland lining, and the white voids represent luminal spaces.

Different electrical impedance parameters that can be gauged from tissue
Different electrical impedance parameters that can be gauged from tissue. The blue bars denote cancer while the other bars denote benign tissues found within the prostate, a difference that drives our research effort. Aca (Adenocarcinoma of the prostate), BPH (benign prostatic hyperplasia), Gl (normal glandular tissue), Str (stromal tissue)