Construction and Verification of a Portable Diffuse Reflectance Spectroscopy System for Clinical Studies
Date Issued
2015
Date
2015
Author(s)
Chuang, Min-Jie
Abstract
The research is to construct a portable diffuse reflectance spectroscopy system that measures diffuse light using a multi-mode optical fiber bundle with different source to detector fiber distances, and using fitting tools to extract tissue optical parameters from the diffuse reflectance spectra for use as a clinical research measurement system. Clinically, diagnosis of esophageal tissue dysplasia is performed by professionally trained doctors by endoscope visual examination and invasive tissue biopsies. This study hopes, by way of non-invasive optical diagnostics, to avoid patient''s pain or wound infection and provide reliable optical parameters to aid in doctor’s diagnoses. Many literature has shown that the use of diffuse reflectance spectroscopy or other spectroscopic techniques, such as fluorescence spectroscopy and light scattering spectroscopy, can extract a set of optical parameters as well as distinguish between normal or diseased tissue, such as oral, colon, skin, cervix, and provide reliable diagnostic information to assist medical personnel. The system uses a verified forward Monte Carlo simulated spectrum to correct the tissue diffuse reflectance spectra. According to the results of tissue phantoms measured using the current system, diffuse reflectance spectra’s of SDS distances of 0.24, 0.26, 0.49, 0.54, 0.76, and 0.78mm between wavelengths of 400 to 700nm show R Square values up to more than the 0.9 standard. In normal oral tissue diffuse reflectance spectra fitting results, for wavelengths 414, 545, and 575nm, hemoglobin uptake and absorption, and scattering coefficients are very close to those reported in previous literature. Thus, these systems can take advantage of this information for precancerous lesions statistical analysis. In the future, the system can be expected to directly measure esophageal tissue and use reverse Monte Carlo for precise fit of the measured spectrum to extract or compare tissue optical parameters such as the scattering coefficient, absorption coefficient, hemoglobin concentration, oxygen ratio, collagen concentration and thickness of the mucosal membrane.
Subjects
diffuse reflectance spectroscopy
spectroscopy systems
scattering coefficient
absorption coefficient
SDGs
Type
thesis
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