Light-induced autofluorescence spectroscopy for tissue diagnosis of GI lesions

Background: The present article describes light-induced autofluorescence sp ectroscopy using violet-blue excitation light for endoscopic in vivo measur ements in the upper Gi tract. The spectra of normal mucosa, cancer, and dys plastic lesions of the esophagus and stomach are presented and compared. Methods: Over 120 spectra were obtained in 11 patients of normal mucosa and malignant lesions in the esophagus and stomach during routine endoscopy. A special light source capable of delivering either white or violet-blue lig ht was used for the excitation of tissue autofluorescence via the endoscope . Endogenous fluorescence spectra emitted by the tissue were collected with a fiberoptic probe and analyzed with a spectrograph. After spectrographic measurements biopsies were taken for definitive classification of histopath ologic status. Results: As compared with normal mucosa, (pre) cancerous lesions were assoc iated with special changes in the emitted fluorescence spectra. The spectro graphic records were influenced by the intensity of the illumination and on the position of the probe (distance and angle). Conclusion: Fluorescence spectroscopy with a slightly modified conventional light source might be useful for the endoscopic detection of dysplasia and early-stage carcinoma in the upper GI tract. Prospective trials need to de termine the sensitivity and specificity of this new method.