Electrical impedance-based biopsy for prostate cancer detection

Currently biopsy is considered the gold standard for diagnosis of prostate cancer in humans, although it samples only 19mm(3) volume of prostate, corresponding to 0.95% of a 50cm(3) prostate gland for a regular 12-core biopsy procedure. The aim of this study was to increase the sampling volume by incorporating electrical impedance spectroscopy (EIS) into the standard biopsy needle. Electrical impedance can act as a reliable biomarker for distinguishing malignant from benign tissues in human prostate. The EIS biopsy needle allows tip of the needle to act as sensor to measure the electrical impedance of the tissue core extracted. The sensitivity of the prototype device was evaluated in a series of saline bath experiments. We demonstrated that EIS biopsy needle senses 286.92 mm(3) of volume of the tissue on either side of the needle trajectory for each core, adding up to 2 X 12 X 286.92 = 6886.08 mm(3) or 13.8% of tissue's volume. Thus, measuring electrical properties in addition to core extraction is expected to enhance the sensitivity and specificity of the device. A few experiments have been conducted on ex vivo porcine samples to envisage EIS biopsy needle's ability in distinguishing two different kinds of tissues.