Combined fluorescence and reflectance spectroscopy: in vivo assessment of oral cavity epithelial neoplasia

Abstract

Summary form only given. Fluorescence and reflectance spectroscopy are promising techniques for early diagnosis of neoplasia. Consistent differences have been found in spectra of normal and neoplastic oral mucosa. However, the optimal wavelengths to discriminate between normal, and neoplastic tissue in vivo have not been identified, nor has the diagnostic ability of reflectance and fluorescence spectroscopy been compared. To answer this question, the authors have designed and tested a system to collect autofluorescence emission spectra at 18 different excitation wavelengths (330 to 500 nm). These spectra are assembled into excitation emission matrices (EEM). Reflectance spectra are measured from 300-900 nm. In vivo fluorescence EEMs and reflectance spectra of normal and neoplastic oral mucosa were obtained. The system consists of: an Xe arc lamp, monochromator and filter wheel, which provides excitation; a fiber-optic probe, which directs light to the tissue and collects fluorescence from one location and diffusely reflected light from three locations; and a filter wheel, imaging spectrograph and CCD, which detects the reflectance and fluorescence. The probe consists of 46 optical fibers in two concentric bundles.