A real-time 4-bit imaging electrical impedance sensing biopsy needle for prostate cancer detection

摘要

Introduction: Prostate cancer is the second leading cause of cancer death in men. Biopsy serves as the primary tool for cancer diagnoses in these men. However, false-negative diagnosis following biopsy can be as high as 30% and even when detected via biopsy it can be difficult to accurately grade the cancer. Electrical properties of prostate cancer have been reported to be significantly different than benign prostate. We hypothesize that a custom tetrapolar-based electrical impedance sensing biopsy (EIS-Bx) needle will be able to detect electrical properties of surrounding tissue and provide a "4 bit" image for guidance to potential cancer locations. Methods: A custom EIS-Bx device was designed using four gold-plated electrode traces on a standard biopsy needle. A novel small form-factor impedance analyzer was designed to interface with the EIS-Bx needle. The EIS-Bx device was submerged in a saline bath while a high contrast inclusion was rotated in 90-degree increments around the needle. At each location, the impedance of 4 electrode configurations was recorded at 7 frequencies (ranging from 1kHz to 100kHz). The impedances of each quadrant were compared with the inclusion location to examine spatial differentiation. Results: Bipolar measurements clearly detected impedance changes correlated to inclusion presence across frequencies. These results validate the hypothesis of potential "4-bit" imaging for cancer detection and diagnostic guidance. Conclusion: Initial experiments successfully demonstrate spatial sensitivity to a moving inclusion using the EIS-Bx device. Future work will investigate the ability to differentiate cancer from benign tissue ex-vivo with quadrant specific resolution and to display this as a real-time map of prostate pathology.