Time-resolved fluorescence spectroscopy as a diagnostic technique of oral carcinoma: Validation in the hamster buccal pouch model.

OBJECTIVE To investigate the benefit of using time-resolved, laser-induced fluorescence spectroscopy for diagnosing malignant and premalignant lesions of the oral cavity. DESIGN The carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) was applied to 1 cheek pouch of 19 hamsters. The contralateral pouch and the cheek pouches of 3 hamsters without DMBA exposure served as controls. SETTING University of California, Davis. PARTICIPANTS Twenty-two golden/Syrian hamsters. INTERVENTION A nitrogen pulse laser was used to induce tissue autofluorescence between the wavelengths of 360 and 650 nm. MAIN OUTCOME MEASURES Spectral intensities and time-domain measurements were obtained and compared with the histopathologic findings at each corresponding site. RESULTS Spectral intensities and lifetime values at 3 spectral bands (SBs; SB1 = 380 +/- 10 nm; SB2 = 460 +/- 10 nm, and SB3 = 635 +/- 10 nm) allowed for discrimination among healthy epithelium, dysplasia, carcinoma in situ, and invasive carcinoma. The lifetime values at SB2 were the most important when distinguishing the lesions using only time-resolved parameters. An algorithm combining spectral fluorescence parameters derived from both spectral and time-domain parameters (peak intensities, average fluorescence lifetimes, and the Laguerre coefficient [zero-order]) for healthy epithelium, dysplasia, carcinoma in situ, and invasive carcinoma provided the best diagnostic discrimination, with 100%, 100%, 69.2%, and 76.5% sensitivity and 100%, 92.2%, 97.1%, and 96.2% specificity, respectively. CONCLUSIONS The addition of time-resolved fluorescence-derived parameters significantly improves the capability of fluorescence spectroscopy-based diagnostics in the hamster buccal pouch. This technique provides a potential noninvasive diagnostic instrument for head and neck cancer.