REAL-TIME FIBER OPTIC RAMAN SPECTROSCOPY FOR EARLY DIAGNOSIS OF PRECANCER AND CANCER IN VIVO IN THE UPPER GASTROINTESTINAL TRACT

Abstract

Gastrointestinal malignancies including esophagus and gastric cancer are diseases with high mortality rates. Early detection and diagnosis remain the most critical measures to improve the survival of the patients. Raman spectroscopy is an inelastic light scattering technique with high molecular specificity. We develop a novel image-guided fiber-optic rapid Raman spectroscopy technique for in vivo tissue measurements in patients during clinical endoscopic examinations. An on-line diagnostic framework is developed for prospective real-time cancer diagnosis. To significantly improve the sensitivity for epithelial precancerous lesions, a novel fiber-optic confocal Raman endoscopy technique is presented using a beveled fiber-optic Raman probe coupled with a sapphire ball lens. We apply the fiber-optic confocal Raman technique prospectively in esophageal patients. Finally, we develop a second generation multiplexing Raman endoscopy technique using a customized volume phase holographic grating that simultaneously acquires both fingerprint and high wavenumber tissue Raman spectra in high resolution for improved tissue characterization.