The Effect of Probe Pressure on In Vivo Single Fiber Reflectance Spectroscopy

ABSTRACT: Reflectance spectroscopy is a method to noninvasively quantitate the scattering and absorption properties of a turbid medium like tissue. The absorption and scattering properties can be used in diagnosis of different diseases such as cancer. Dependence of the acquired spectra to the environmental and physiological factors like probe pressure and habits of the person are being sought out in this thesis. Our applied method, single fiber reflectance (SFR) spectroscopy, uses a single fiber for delivery and detection of the visible light. The SFR spectrum can be fitted by a nonlinear model of the scattering and absorption properties of the tissue under investigation. In this study, SFR measurements are made by a fiber-optic probe gently placed on the lip tissue of some volunteers. The effect of variation in the probe pressure during the measurements is evaluated through the probable change in the extracted parameters from the fitted spectra. In order to do this, first the most appropriate model for the human lip reflectance spectrum is found. Then, the variation in the extracted parameters due to different probe pressures or physiologic characteristics of the volunteers is investigated. Keywords: reflectance spectroscopy - single fiber reflectance spectroscopy. …………………………………………………………………………………………………………………………