VAIL, CO USA (UroToday.com) - Light interacts with biological tissue in a variety of ways. The optical properties of tissues are determined by their molecular composition and cellular morphology.
Malignant transformation is associated with structural, genotypic/phenotypic cellular modifications, and biochemical changes in the extracellular environment, which consequently alters spectroscopic, metabolic, and microscopic properties. Specifically, fluorescence emissions from prostate tissue depend on concentration of natural fluorophores (e.g., tryptophan, collagen, NADH) which are altered by the presence of carcinoma. 
Thus, changes in fluorescence spectra can be used for prostate cancer diagnosis. Since light is scattered at cells or intracellular structures, diffuse reflectance spectra contains information regarding tissue morphology and architecture. Thus, changes in diffuse reflectance spectra can also be used to diagnose prostate cancer as well as histopathological grade. A minimally invasive optical biopsy needle which can obtain prostate biopsies after optical characterization of tissue has been developed. This needle has an optical sensor at the tip of the needle for tissue excitation and capture emission spectra. Following spectral acquisition and tissue characterization, a tissue biopsy core from the same tissue can be obtained for precise histopathological correlation. First-in-Human clinical trial at the University of Colorado Hospital, this optical biopsy needle successfully diagnosed prostate cancer with 84% sensitivity, 90% specificity, and 97% negative predictive value. Introduction of this technology into clinical settings is expected to overcome perceived limitations associated with current TRUS-guided biopsies and provide accurate data to significantly improve clinical management of this disease.
Presented by Priya N. Werahera, PhD at the 24th International Prostate Cancer Update - February 19 - 22, 2014 - Cascade Conference Center - Vail, Colorado USA