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Diagnostic and Therapeutic Endoscopy
Volume 5 (1999), Issue 2, Pages 113-118

5-Aminolaevulinic Acid (ALA) for the Fluorescence Detection of Bronchial Tumors

1Division of Pneumology, Department of Medicine, Klinikum Innenstadt, University of Munich, Ziemssenstraße 1, München D-80336, Germany
2Hospital for Pneumology, University of Munich, Germany
3Laser Research Institute, Department of Urology, University of Munich, Germany

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


At the moment only early detection of lung cancer offers a good prognosis for the patients. Conventional white light endoscopy is mostly insufficient for early diagnosis. Therefore we developed a system of fluorescence diagnosis using 5-aminolaevulinic acid (ALA) exogeneously applied. As precursor of the heme synthesis it is metabolized to protoporphyrin IX – a red fluorescent substance. Therefore protoporphyrin IX accumulates in tumorous and premalignant tissue, and can be directly visualized by fluorescence bronchoscopy. Excitation with blue light (380–435 nm) causes a red fluorescence, which can be detected after filtering most of the blue component with the naked eye or a camera system. After earlier work with laser systems and cold light sources we now use the system D-Light AF for the fluorescence diagnosis using ALA-induced protoporphyrin IX fluorescence.