NON-INVASIVE OPTICAL DETECTION OF EPITHELIAL CANCER USING OBLIQUE INCIDENCE DIFFUSE REFLECTANCE SPECTROSCOPY
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This dissertation describes the design, fabrication and testing of an oblique incidence diffuse reflectance spectrometry (OIDRS) system for in-vivo and noninvasive detection of epithelial cancer. Two probes were fabricated using micromachining technology, which plays a significant role in the probe development by enabling device miniaturization, low-cost fabrication and precise assembly. The fist probe was developed and clinically tested for skin cancer detection. This probe consists of three source fibers, two linear array of collection fibers and four micromachined positioning devices for accurate alignment of the fibers. The spatially resolved diffuse reflectance spectra from 167 pigmented and 78 non-pigmented skin abnormalities were measured and used to design a set of classifiers to separate them into benign or malignant ones. These classifiers perform with an overall classification rate of 91%. The absorption and reduced scattering coefficient spectra were estimated to link the anatomic and physiologic properties of the lesions with the optical diagnosis. The melanoma cases presented larger average absorption and reduced scattering spectra than the dysplastic and benign ones. A second probe was designed to demonstrate the feasibility of a miniaturized ?side viewing? optical sensor probe for OIDRS. The sensor probe consists of a lithographically patterned polymer waveguides chip and two micromachined positioning substrates. This miniaturize probe was used to measure twenty ex-vivo esophageal samples. Two statistical classifiers were designed to separate the esophageal cases. The first one distinguishes benign and low dysplastic from high dysplastic and cancerous lesions. The second classifier separates benign lesions from low dysplastic ones. Both classifiers generated a classification rate of 100%.