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Proceedings Paper

5-ALA/PpIX fluorescence detection of gastrointestinal neoplasia
Author(s): Ekaterina G. Borisova; Borislav Vladimirov; Ivan Terziev; Radina Ivanova; Latchezar Avramov
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Paper Abstract

In the recent study delta-ALA/PpIX is used as fluorescent marker for dysplasia and tumor detection in esophagus, stomach and colon. ALA is administered per os six to eight (depending on the lesion location) hours before measurements at dose 20mg/kg weight. High-power light-emitting diode at 405 nm is used as an excitation source. Special opto-mechanical device is built for the LED to use the light guide of standard video-endoscopic system. Through endoscopic instrumental channel a fiber is applied to return information about fluorescence to microspectrometer. The fluorescence detected from tumor sites has very complex spectral origins. It consists of autofluorescence, fluorescence from exogenous fluorophores and re-absorption from the chromophores accumulated in the tissue investigated. Spectral features observed during endoscopic investigations could be distinct as the next regions: 450-630 nm region, where tissue autofluorescence is observed; 630-710 nm region, where fluorescence of PpIX is clearly pronounced; 530-580 nm region, where minima in the autofluorescence signal are observed, related to re-absorption of oxy-hemoglobin in this spectral area. Endogenous and exogenous fluorescence spectra are used to develop simple but effective algorithm, based on dimensionless ratio of the signals at 560 and 635 nm, for differentiation of normal/abnormal gastrointestinal tissues. Very good correlation between fluorescence signals and histology examination of the lesions investigated is achieved.

Paper Details

Date Published: 7 July 2009
PDF: 6 pages
Proc. SPIE 7368, Clinical and Biomedical Spectroscopy, 736824 (7 July 2009); doi: 10.1117/12.831604
Show Author Affiliations
Ekaterina G. Borisova, Institute of Electronics (Bulgaria)
Borislav Vladimirov, Univ. Hospital Queen Giovanna (Bulgaria)
Ivan Terziev, Univ. Hospital Queen Giovanna (Bulgaria)
Radina Ivanova, Univ. Hospital Queen Giovanna (Bulgaria)
Univ. Hospital of Endocrinology (Bulgaria)
Latchezar Avramov, Institute of Electronics (Bulgaria)

Published in SPIE Proceedings Vol. 7368:
Clinical and Biomedical Spectroscopy
Irene Georgakoudi; Jürgen Popp; Katarina Svanberg, Editor(s)

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