Detection of positive cancer margins intra-operatively during nephrectomy and prostatectomy using optical reflectance spectroscopy

In recent years optical spectroscopies have become the basis for popular research activity directed towards the development of novel, noninvasive technologies for tissue diagnostics. The motivation for my research was to eliminate the need for surgical removal of tissue samples for biopsy and histology. With the help of an optical probe placed on or near the surface of the tissue, Near Infrared (NIR) and visible light spectroscopy can provide diagnostic signatures, non-invasively and in real time. While the ultimate goal of my research development is the elimination of the need to remove tissue samples, the technology that I am developing can also be used to provide additional guidance in real time during laparoscopic surgery.;In this study, optical reflectance spectroscopy with short source-detector separation is used as a minimally invasive technique to differentiate normal tissues from tumor lesions ex-vivo. Reflectance spectra (400 nm--1000 nm) were acquired with an optical probe from human specimens after radical or partial nephrectomys and radical prostatectomy. The main aim of my thesis was to differentiate between normal and tumor tissues and then extend the application to differentiate between benign and malignant tissues. The study involved 13 human subjects' specimens for prostate measurements and 23 human subjects's specimens for kidney measurements. My study reveals that for kidney tissues, promising parameters were (1) the slope of the reflectance spectrum from 630 nm to 900 nm, (2) correlation coefficients between the normal and tumor (or between benign and malignant) reflectance spectra from 560 nm to 630 nm, (3) and two-wavelength-intensity classifications. For prostate tissue, promising parameters were the slope of the reflectance spectrum from 630 nm to 900 nm. Furthermore, NIR reflectance spectroscopy can be further used with an optical probe having larger source-detector separations to image deep tissues. A "smart" probe can be designed which can be used intra-operatively to provide real time surgical guidance during laparoscopic surgery.