Reflectance-based optical diagnosis of epithelial pre-cancer: modeling spectroscopic measurements, fiber-optic probe design considerations, and analysis of tissue micro-optical properties
Year: 2005
Type: dissertation
Abstract: Optical diagnostic techniques have the potential to improve early detection \nof pre-cancerous changes in tissues. These techniques can be implemented in real \ntime without the need for biopsy removal, and are expected to have major impact \nin clinical practice. This dissertation describes a series of modeling studies aimed \nat establishing an improved understanding of reflectance properties of normal and \npre-cancerous epithelial tissues, with the ultimate goal of revealing the potential \nof reflectance-based optical diagnosis of epithelial pre-cancer. \nThe first part of the dissertation presents Monte Carlo modeling studies to \nprovide a quantitative understanding of contrast observed in reflectance spectra of \nnormal and pre-cancerous epithelial tissues. Simulation results provide important \ninsights into the specific contributions of different epithelial and stromal optical \nparameters to the overall spectral response. Predictions from simulations agree \nwell with in vivo measurements from cervical tissue, and can successfully \ndescribe differences in spatially resolved reflectance spectra of normal and precancerous \ntissue sites. Monte Carlo modeling is also used to evaluate different \nfiber-optic probe geometries with respect to sampling depth and to propose a \nprobe design that can resolve spectral information from epithelium and stroma. \nThe proposed design can reveal diagnostic features inherent in optical signatures \nunique to each of the two tissue layers. \nThe research presented in the rest of the dissertation is targeted towards \nanalyzing the micro-optical properties of epithelial tissues. The Finite-Difference \nTime-Domain (FDTD) method, a popular computational technique for solution of \nproblems in electromagnetics, is used to model light scattering from epithelial \ncells and collagen fibers. FDTD simulation results indicate that morphological \nand structural changes associated with pre-cancer progression lead to significant \nalterations in light scattering properties of these microscopic tissue constituents. \nThe modeling studies presented in this dissertation provide a framework to \nmeaningfully interpret optical signals obtained from epithelial tissues and to \noptimize design of optical sensors for in vivo reflectance measurements. The \nresults obtained throughout this research will aid in development and assessment \nof optical spectroscopic and imaging techniques for early, noninvasive diagnosis \nof epithelial pre-cancer.
Author: Dizem Arifler
Language: English
Subfield: Radiology, Nuclear Medicine and Imaging
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1947504321