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Title: Ace Day 1995: AUTOFLUORESCENT SPECTRA AND MICROSCOPE IMAGES OF BLADDER TISSUE FOR THE DIAGNOSIS OF PRE-CANCEROUS CHANGES

Written by: J.T. Arendt and R.M. Cothren, Ph.D.

Institutions: The Cleveland Clinic Foundation and The Ohio State University, Department of Biomedical Engineering

Date Written: April 19, 1995

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An ongoing study attempts to determine whether using in vivo fluorescence spectroscopy performed through an endoscope or rigid cystoscope can distinguish between normal bladder mucosa and that with papillary tumors, dysplasia, carcinoma in situ (CIS), or invasive cancer. The probe, which is small enough to easily fit down the auxiliary channel of an endoscope, contains a single excitation fiber and six collection fibers all bound together in plastic. The probe produces a 750 um wide spot that penetrates about half a millimeter into the tissue. A thematically-cooled multi-channel-plate (MCP) intensifier connected to a optical multi-channel analyzer (OMA) with a 1024 diode array, of which 700 diodes receive signal data, collects the returned fluorescence spectra. Since the availability of cystoscopy cases is low, the same probe is used on resected bladders from cystectomy cases. For the cystectomy cases, the fluorescence spectra are measured within half an hour after the bladder is removed. Spectra are collected at five or six sites on the dissected bladder, at both 370 nm and 400 nm excitation wavelengths. Biopsies are taken from the same locations that the spectra are measured. A pathologist analyzes the Hematoxylin and Eosin (H&E) stained microscope slides created from the biopsied specimens and makes a diagnosis. Of the six cystectomy cases so far, the pathologist has examined five cases. For 25 samples from 5 resected bladders, the diagnosis is 8 benign, 3 dysplasia, 8 CIS, 4 invasive cancer, and 2 undetermined. Using the emission spectra corresponding to these biopsied samples, with emission amplitudes taken at 400 nm, 600 nm, and 680 nm, various ratios and normalizations have been graphed that appear to indicate trends that may lead to the ability to make a future diagnosis.

In addition, a fluorescence microscope with a backlit, thermoelectrically-cooled CCD camera will soon record images which reveal the fluorescence from the fluorophores within unstained frozen sections of bladder tissue biopsied from the same resected bladders. Taking frozen biopsies is just beginning for these cases, but a few images of benign bladder tissue have been taken using tissue stored in the freezer for which fluorescence spectra was not taken show that collagen is the primary fluorophore with the cytoplasm of the epithelium appearing to be a secondary fluorophore. Along with images of normal tissue for which spectra have been taken, images will be taken of dysplasia, carcinoma in situ, and invasive cancer.

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