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Proceedings Paper

In-vivo kinetics of ALA-induced fluorescence in the canine oral cavity: influence of drug dose and tissue type
Author(s): Vijay Vaidyanathan; Sohi Rastegar; Theresa W. Fossum; P. Flores; E. W. J. van der Breggen; N. G. Egger; Steven L. Jacques; Massoud Motamedi
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Paper Abstract

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.

Paper Details

Date Published: 16 June 1997
PDF: 5 pages
Proc. SPIE 2975, Laser-Tissue Interaction VIII, (16 June 1997); doi: 10.1117/12.275483
Show Author Affiliations
Vijay Vaidyanathan, Texas A&M Univ. (United States)
Sohi Rastegar, Texas A&M Univ. (United States)
Theresa W. Fossum, Texas A&M Univ. (United States)
P. Flores, Texas A&M Univ. (United States)
E. W. J. van der Breggen, Univ. of Texas Medical Branch at Galveston (Netherlands)
N. G. Egger, Univ. of Texas Medical Branch at Galveston (United States)
Steven L. Jacques, Oregon Medical Laser Ctr. (United States)
Massoud Motamedi, Univ. of Texas Medical Branch at Galveston (United States)


Published in SPIE Proceedings Vol. 2975:
Laser-Tissue Interaction VIII
Steven L. Jacques, Editor(s)

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