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16 June 1997 In-vivo kinetics of ALA-induced fluorescence in the canine oral cavity: influence of drug dose and tissue type
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Proceedings Volume 2975, Laser-Tissue Interaction VIII; (1997)
Event: BiOS '97, Part of Photonics West, 1997, San Jose, CA, United States
Fluorescence spectroscopic detection and photodynamic therapy may provide an effective approach for early detection and treatment of oral cancer. Thus the development of a safe photosensitizer that could enhance the spectroscopic contrast between normal and neoplastic tissue, while allowing for selective photosensitization and treatment of pre-malignant and malignant lesions in the oral cavity, is highly desired. In this study, the pharmacokinetics and a safety of 5-aminolevulinic acid (ALA) that could induce an endogenous precursor of protoporphyrin IX and heme in the biosynthetic pathway was investigated. Two doses of ALA:25 and 75 mg/kg were administered intravenously to 4 and 3 dogs, respectively. A 'wash-out' period of 1 week between administration of each does was allowed to ensure against PpIX build-up. Using an optical multichannel analyzer, the fluorescence from the oral cavity was recorded at 3 sites: buccal mucosa, gums, and the tongue, and also from a remote site, the skin. A fiber optic probe was used to deliver excitation and collect the emitted fluorescence. Results showed that the ALA-induced fluorescence reached a peak at 2-4 hours, and returned to baseline in 24-31 hours. The dogs were stable during the course of the study, minimal vomiting was noted. In conclusion, the study showed that higher doses result in a higher peak at a later time.It was observed that different tissues have different pharmacokinetic response, the tongue and the gums have the highest peak fluorescence values, followed by the buccal mucosa and skin.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Vijay Vaidyanathan, Sohi Rastegar, Theresa W. Fossum D.V.M., P. Flores, E. W. J. van der Breggen, N. G. Egger, Steven L. Jacques, and Massoud Motamedi "In-vivo kinetics of ALA-induced fluorescence in the canine oral cavity: influence of drug dose and tissue type", Proc. SPIE 2975, Laser-Tissue Interaction VIII, (16 June 1997);


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