Optimizing Autofluorescence Bronchoscopy(Diagnosis and Treatment of Early Stage Central Type Lung Cancer)(The 23rd Annual Congress of the Japan Society for Bronchology)

Dual wavelength autofluorescence(AF)imaging bronchoscopy is optimized by studying the AT excitation-emission matrix over a wide spectral range. This study was carried out under endoscopic conditions in patients with various stages of malignancy as proven by biopsy. The results show major AF spectral differences between(1)healthy bronchial mucosa, (2)metaplasia or inflammation, and(3)dysplasia or carcinomain situ. The optimal AF excitation wavelength at the applied conditions was found to be near 410 nm. It is suggested that red backscattered light may be a better reference for the disease-related decrease in green AF intensity than the red fluorescence itself. An imaging AF bronchoscope was constructed based on these findings which was tested on 50 patients. The AF results appear to be superior to those obtained by white light bronchoscopy. The combined use of both techniques leads to a much improved positive predictive value for the identification of early stage central lung squamous cell malignancy as compared to each technique used by itself.