Detection of premalignant oral lesions in hamsters with an endoscopic fluorescence imaging system

BACKGROUND. Various methods of detecting cancer with fluorescence have been developed. One type of fluorescence is based on the rumor-localizing prope rties of certain dyes. However, the phototoxicity of most known tumor-local izing dyes hinders the safe use of such diagnostic methods. The authors hav e developed a fluorescence imaging system to detect the distribution of a n ontoxic dye, fluorescein, and they have evaluated the feasibility of the sy stem by using it to detect oral dysplastic lesions in hamsters. METHODS. Dysplasia was induced in the cheek pouches of hamsters by applicat ion of the carcinogen 9,10-dimethyl-1,2-benzantracene. Fluorescein was admi nistered to the hamsters either intravenously or orally before the fluoresc ence examination. The endoscopic fluorescence system produced dye-distribut ion images of both treated and control pouches. Two fluorescence images in different spectral regions were processed for each dye image. Biopsy materi al from both pouches was examined histopathologically. RESULTS. The accumulation of fluorescein was detected in 22 of 23 specimens containing dysplastic lesions. CONCLUSIONS, These results demonstrate the utility of this fluorescein accu mulation method in the detection of dysplasia. The accumulation of fluoresc ein in dysplastic lesions may point to acidification of interstitial medium in such lesions. (C) 1999 American Cancer Society.