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Proceedings Paper

Pharmacokinetics of endogenous porphyrins induced by 5-aminolevulinic acid as observed by means of laser-induced fluorescence from several organs of tumor-bearing mice
Author(s): Ronald Sroka; Reinhold Baumgartner; Wolfgang Beyer; Liebwin Gossner; T. Sassy; Susanne Stocker
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Paper Abstract

Photodynamic therapy (PDT) and photodynamic diagnosis (PDD) add support to efficient treatment modalities of superficial and early stage cancer. Recently 5-aminolevulinic acid (5-ALA), a precursor of hemoglobin in the hem biosynthetic pathway, was used to stimulate endogenous porphyrin production. The time dependency of 5-ALA induced porphyrin fluorescence has been investigated on several normal tissues as well as on a tumor in an in-vivo tumor model (human gastrointestinal adenocarcinoma Grade II, UICC IIa). 5-ALA has been administered intravenously at a concentration of 50 mg/(kg bw). With respect to a certain time schedule the animals were sacrificed and 12 different organs as well as the tumor were removed. Using laser-induced fluorescence techniques the emission spectra in the range of (lambda) equals (550-750) nm were detected from the tissues after excitation with light of the wavelength (lambda) equals (411 +/- 4) nm. For quantitative evaluation the integral fluorescence intensity at (lambda) equals (635 +/- 2) nm of the porphyrin specific spectra has been determined. All tissues showed porphyrin fluorescence, while brightest fluorescence has been detected from the tumor. With respect to the other tissues the relative tumor selectivity showed a maximum ratio at 406 h post injection. The kinetics of the porphyrin fluorescence intensity of the organs follow different time dependencies. Simple mathematical pharmacokinetic models are developed and discussed.

Paper Details

Date Published: 12 April 1995
PDF: 8 pages
Proc. SPIE 2387, Advances in Laser and Light Spectroscopy to Diagnose Cancer and Other Diseases II, (12 April 1995); doi: 10.1117/12.206833
Show Author Affiliations
Ronald Sroka, Ludwig-Maximilians-Univ. Muenchen (Germany)
Reinhold Baumgartner, Ludwig-Maximilians-Univ. Muenchen (Germany)
Wolfgang Beyer, Ludwig-Maximilians-Univ. Muenchen (Germany)
Liebwin Gossner, Univ. Erlangen-Nuernberg (Germany)
T. Sassy, Ludwig-Maximilians-Univ. Muenchen (Germany)
Susanne Stocker, Ludwig-Maximilians-Univ. Muenchen (Germany)

Published in SPIE Proceedings Vol. 2387:
Advances in Laser and Light Spectroscopy to Diagnose Cancer and Other Diseases II
Robert R. Alfano, Editor(s)

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