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Proceedings Paper

ALA-based fluorescence diagnosis of malignant oral lesions in the presence of bacterial porphyrin formation
Author(s): P. Schleier; A. Berndt; K. Zinner; W. Zenk; W. Dietel; W. Pfister
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Paper Abstract

The aminolevulinic acid (5-ALA) -based fluorescence diagnosis has been found to be promising for an early detection and demarcation of superficial oral squamous cell carcinomas (OSCC). This method has previously demonstrated high sensitivity, however this clinical trial showed a specificity of approximately 62 %. This specificity was mainly restricted by tumor detection in the oral cavity in the presence of bacteria. After topical ALA application in the mouth of patients with previously diagnosed OSSC, red fluorescent areas were observed which did not correlate to confirm histological findings. Swabs and plaque samples were taken from 44 patients and cultivated microbiologically. Fluorescence was investigated (OMA-system) from 32 different bacteria strains found naturally in the oral cavity. After ALA incubation, 30 of 32 strains were found to synthesize fluorescent porphyrins, mainly Protoporphyrin IX. Also multiple fluorescent spectra were obtained having peak wavelengths of 636 nm and around 618 nm - 620 nm indicating synthesis of different porphyrins, such as the lipophylic Protoporphyrin IX (PpIX) and hydrophylic porphyrins (water soluble porphyrins, wsp). Of the 32 fluorescent bacterial strains, 18 produced wsp, often in combination with PpIX, and 5 produced solely wsp. These results clarify that ALA-based fluorescence diagnosis without consideration or suppression of bacteria fluorescence may lead to false-positive findings. It is necessary to suppress bacteria fluorescence with suitable antiseptics before starting the procedure. In this study, when specific antiseptic pre-treatment was performed bacterial associated fluorescence was significantly reduced.

Paper Details

Date Published: 6 March 2006
PDF: 8 pages
Proc. SPIE 6139, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV, 613908 (6 March 2006); doi: 10.1117/12.646533
Show Author Affiliations
P. Schleier, Friedrich Schiller Univ. Jena (Germany)
A. Berndt, Friedrich Schiller Univ. Jena (Germany)
K. Zinner, Friedrich Schiller Univ. Jena (Germany)
W. Zenk, Friedrich Schiller Univ. Jena (Germany)
W. Dietel, Friedrich Schiller Univ. Jena (Germany)
W. Pfister, Friedrich Schiller Univ. Jena (Germany)

Published in SPIE Proceedings Vol. 6139:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XV
David Kessel, Editor(s)

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