Towards Microendoscopic Electrical Impedance Tomography for Intraoperative Surgical Margin Assessment
Ryan J. Halter, Young-Joong Kim, Dartmouth College & Duke University
Volume 61, Issue 11, Page: 2779-2786
Over 200,000 men are diagnosed each year with prostate cancer. Surgical removal of the prostate represents a treatment option chosen by 140,000 men annually in which the primary objective is to eradicate all prostate cancer cells within the body. Cancer cells identified on the margins of the surgically removed prostate suggest that cancer cells were left within the body. These positive surgical margins (PSMs) are indications for disease recurrence and suggest noxious adjuvant or salvage therapies. Unfortunately, no clinical protocols are routinely used to intraoperatively assess surgical margin status during prostate surgery. Instead, margins are evaluated through pathological assessment of the prostate following radical prostatectomy (RP), when it is too late to provide additional surgical intervention.
Significantly different electrical property signatures have been observed between benign and malignant prostate tissues, and we hypothesize that gauging these properties intraoperatively has the potential to provide clinically relevant information regarding surgical margin pathology. To leverage this contrast for use in evaluating surgical margins intraoperatively, we have developed a novel Microendoscopic Electrical Impedance Tomography (EIT) probe that can be introduced into the surgical space through a small access port that accommodates robotically-controlled instruments, is sufficiently flexible to be manipulated by the robotic instruments, is capable of distinguishing between tissue types on a sub-mm scale (~500 m), and can sense sub-surface tissues to a depth of ~1.5 mm. This device represents a unique approach to intraoperatively evaluating surgical margins during robot-assisted radical prostatectomy procedures and is currently being prepared for use in in vivo human trials.
Key Words: Electrical impedance tomography, prostate cancer, surgical margin assessment, radical prostatectomy