Fluorescence endoscopy instrumentation for improved tissue characterization.

An endoscopic instrument for normal optical inspection and simultaneous fluorescence characterization is described. The equipment is primarily intended for early cancer detection using characteristic fluorescence from the tumor-seeking agent hematoporphyrin derivative. A dimensionless ratio of two fluorescence intensities is monitored making the equipment insensitive to target distance and surface topography. A measurement example is given and possible improvements are discussed.