Real-time endoscopic fluorescence imaging for early cancer detection in the gastrointestinal tract

The utility of autofluorescence imaging for early lung cancer detection has been previously demonstrated. The aim of this work is to extend the use of real-time autofluorescence imaging to the early cancer detection in the esophagus, stomach, and colon. A prototype fluorescence imaging system for the gastrointestinal (GI) tract was developed which produces real-time video images of tissue autofluorescence. It consists of a filtered mercury arc lamp light source, two intensified charge coupled device (ICCD) cameras, a fiber optic endoscope, and a computer-based control console. The system is capable of working with three different imaging modalities: (1) conventional white light imaging mode; (2) light induced fluorescence (LIF) imaging mode based on the fluorescence imaging of two wavelength bands (green and red); and (3) light induced fluorescence and reflectance (LIFR) imaging mode based on the combination of a green band fluorescence image and a red–near-IR reflectance image. The imaging wavelength bands were selected based on in vivo fluorescence spectroscopic studies. The fluorescence images (both LIF image and LIFR image) clearly delineate the abnormal tissue areas for biopsy. Early cancer sites are better visualized under fluorescence imaging than under conventional white light examination. Initial clinical tests demonstrated the usefulness of the imaging prototype system for early cancer detection in the GI tract.