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Q: Quantenoptik

Q 30: Poster: Laser in Medicine

Q 30.4: Poster

Friday, April 6, 2001, 12:30–15:00, AT2

Monitoring therapy of rectal cancer by delayed laser-induced endogenous fluorescence — •Bernd Ebert¹, Uwe Sukowski¹, Panagiota Balanou², Thomas Moesta², Tim Handke², Peter Schlag², and Herbert Rinneberg¹ — ¹Physikalisch-Technische Bundesanstalt, Abbestr. 2 - 12, 10587 Berlin — ²Universitätsklinikum Charite, Robert-Rössle-Klinik, Lindenberger Weg 80, 13122 Berlin

Up to now response to neoadjuvant treatment of cancer by radiochemotherapy with or without hyperthermia can not be monitored precisely in vivo. In this study the fluorescence intensity of endogenous porphyrins was used as marker for tumor response. To excite (λ = 505 nm) fluorescence the signal beam of an OPO pumped by the 3^rd harmonic of a Nd:YAG laser was coupled into a fiber inserted into the working channel of a colonoscope. The fluorescence light was collected by the same fiber. To simultaneously record prompt and delayed fluorescence, part of the fluorescence light was optically delayed before spectral analysis. Prior to therapy the fluorescence spectra of tumors generally exhibit strong fluorescence bands originating from porphyrins. If, however, the tumor stage was lowered by the treatment, porphyrin fluorescence was strongly reduced.