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Fluorescence Imaging During Photodynamic Therapy of Experimental Tumors in Mice Sensitized with Disulfonated Aluminum Phthalocyanine ¶
Author(s) -
Cubeddu Rinaldo,
Pifferi Antonio,
Taroni Paola,
Torricelli Alessandro,
Valentini Gianluca,
Comelli Daniela,
D'Andrea Cosimo,
Angelini Valentina,
Canti Gianfranco
Publication year - 2000
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2000)0720690fidpto2.0.co2
Subject(s) - photodynamic therapy , fluorescence , photobleaching , absorption (acoustics) , phthalocyanine , wavelength , chemistry , irradiation , excited state , fibrosarcoma , fluorescence lifetime imaging microscopy , photochemistry , biophysics , materials science , optoelectronics , pathology , optics , medicine , biology , atomic physics , physics , organic chemistry , nuclear physics , composite material
A fluorescence imaging system was used to monitor the emission of disulfonated aluminum phthalocyanine (AlS 2 Pc) during the photodynamic therapy (PDT) of murine tumors. Cells of the MS‐2 fibrosarcoma were injected in mice in two compartments in order to cause the development of tumors in different host tissues. Two drug doses and two uptake times were considered. Moreover, the fluorescence of the AlS 2 Pc was excited using two wavelengths on the opposite sides of the absorption peak to detect a possible change in the absorption spectrum of the sensitizer induced by the PDT. In the tumors, the treatment induces a variation of the fluorescence intensity: in some mice a mild photobleaching takes place, in others a fluorescence enhancement occurs. Which effect predominates depends on the experimental conditions, even though a large spread of data was found amongst mice of the same group. In all mice, independently of the drug dose, uptake time or tumor compartment, a marked increase in the fluorescence signal takes place at the borders of the irradiated area. To quantify this effect we evaluated the ratio between the fluorescence intensities in the peritumoral area and in the tumor itself. This ratio increases monotonically during the PDT, showing a different behavior with the two excitation wavelengths. This indicates that the AlS 2 Pc absorption spectrum shifts toward shorter wavelengths as a result of the irradiation.