The intrinsic fluorescence achieved without dyes (autofluorescence) of bladder tissue, benign mucosa and the various stages of transitional cell carcinoma (TCC), is being characterized. D'Hallewin, et al., and Koenig, et al., are testing autofluorescence spectroscopy for detecting bladder carcinoma using an optical fiber probe inserted down the auxiliary channel of an endoscope. These studies do not include fluorescent microscopy to directly examine the fluorescing structures (fluorophores) within the tissue. Therefore, frozen unstained sections are being imaged on a fluorescence microscope to identify and reveal the morphology and location of the fluorophores. Tissue biopsies taken at endoscopy are immediately frozen in liquid nitrogen. Later, the tissue is cut into 5 μm sections. Serial sections are alternately imaged frozen on the fluorescence microscope or stained with hematoxylin-and-eosin (H&E). The H&E stained slides are reviewed by a pathologist.

A 75-W xenon arc lamp fitted with a 380-nm narrow-band interference filter is coupled to microscope slides on the stage of an Olympus MT-2 inverted microscope.