EP0792618A1 — Imaging system for detecting diseased tissue using native fluorescence in the gastrointestinal and respiratory tract

USPTO Abstract

A system for detecting cancerous or precancerous lesions directs light produced from a mercury arc lamp (100) into an illumination guide (106) of an endoscope. Autofluorescence light produced by the tissue under examination is divided into red and green spectral bands by a dichroic mirror (120). Light in the red and green spectral band is applied to a pair of image intensified CCD cameras (126, 130). The output of the camera that receives light in the red spectral band is coupled to a red video input of a color video monitor (150). Light produced by the camera that receives light in the green spectral band is coupled to the blue and green video inputs of the video monitor. The system produces a false color display, whereby healthy tissue appears cyan in color and cancerous or precancerous lesions appear reddish in color. The image displayed allows the operator to see the lesions within the context of the underlying tissue structures. The color contrast is adjustable to account for the autofluorescence property changes from patient to patient and from location to location.