1 May 1995 Phosphorescent detection of a hyperoxia and hypoxia in tumors during photodynamic action
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Abstract
Highly phosphorescent photosensitizer Pd-tetra (o-methoxy-p-sulfo) phenyl porphyrin ( Pd-MSPP) was used to follow for interaction of its triplets with molecular oxygen in solid tumor of rats in vivo. Half an hour after intravascular injection of 2 mg of Pd-TMSPP in the rat the phosphorescence band having maximum at 710 n.m and life time of photosensitizer triplets have been measured after ns laser pulse excitation at 532 urn in tissues in vivo. The life time of triplets has varied between 100-300 js in different rats and has been independent on the time of laser pulse excitation. Then 2 mg of other photosensitizer MME cb.lorin e6 with absorption band at 660 mm have been injected and photodynamics effects have been investigated by the measurement of life time of Pd-TMSPP triplets depending on free oxygen content in tumor. Decrease of triplet life time of Pd-TMSPP have been observed during 10 mm of tumor exposition what have been interpreted as photoinduced increase of free oxygen content in the tumor. After following continuous exposition of the tumor slow continuous increase of triplet life time of Pd-TMSPP have been detected as result of developing photoinduced hypoxia. The quenching of Pd -TMSPP triplets by cells components in vivo have not been observed after blockade of tumor blood vessels and stopage of oxygen enter in tissues. The quenching of the sensitizer triplets takes place only in the presence of free oxygen in tissue. At least two exponential components of the phosphorescence decay shows that the distribution of the free oxygen is not uniform in tissues.
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Anatoly P. Losev, Anatoly P. Losev, Valentin N. Knukshto, Valentin N. Knukshto, Ivan N. Zhuravkin, Ivan N. Zhuravkin, } "Phosphorescent detection of a hyperoxia and hypoxia in tumors during photodynamic action", Proc. SPIE 2392, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy IV, (1 May 1995); doi: 10.1117/12.208191; https://doi.org/10.1117/12.208191
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