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Proceedings Paper

Two-step excitation in photosensitized tumor therapy
Author(s): Ricardas Rotomskis; Valentinas Mickunaitis; Darius Juodzevicius; Algis S. Piskarskas
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Paper Abstract

The primary process in the usual photosensitized tumor therapy is sensitization from the sensitizers lowest triplet state. Alternatively, the laser light can be pulsed so that excitation occurring over short interval at high peak power can induce two-photon excitation of sensitizers via nonresonant absorption and initiate photodynamic action. The theoretical model has been developed and laser pulse parameters that ensure efficient two-step process have been calculated. In addition, the threshold that separates the two-step process through singlet manifold or triplet manifold was estimated. Both two-step excitation regimes should be initiated with tailored laser pulses. In this work we focus our attention on the characterization of the parameters (the lifetime of excited singlet state, quantum yield of interconversion to the triplet state, etc.) of the most suitable sensitizers for the proposed two-step excitation scheme. On the basis of our model the parameters of the laser pulse and the parameters of the most efficient sensitizer in two-step photosensitization process could be selected.

Paper Details

Date Published: 12 January 1995
PDF: 11 pages
Proc. SPIE 2325, Photodynamic Therapy of Cancer II, (12 January 1995); doi: 10.1117/12.199136
Show Author Affiliations
Ricardas Rotomskis, Vilnius Univ. (Lithuania)
Valentinas Mickunaitis, Vilnius Univ. (Lithuania)
Darius Juodzevicius, Vilnius Univ. (Lithuania)
Algis S. Piskarskas, Vilnius Univ. (Lithuania)

Published in SPIE Proceedings Vol. 2325:
Photodynamic Therapy of Cancer II
Daniel Brault; Giulio Jori; Johan Moan; Benjamin Ehrenberg, Editor(s)

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