FLYORESCENT DOSIMETRY IN PHOTODYNAMIC THERAPY
The long-lived photoexcitations relaxation processes of fluorophores in biological tissues with molecular oxygen presence are investigated. This subject has a practical significance because of the active elaboration of photodynamic therapy and optical diagnostic. The futures of delayed fluorescence and phosphorescence in erythrosine stained healthy and cancer-diseased mammary gland tissues of BYRB-line mice were investigated in vitro. The dominant role of diffusive-mobile molecular oxygen in relaxation of triplet-excited long-life states of the dye molecules in cells is determined. A novel phenomenon of suppression of stained tissue delayed fluorescence under pulsed laser irradiation was revealed. The phenomenon was named as light quenching of delayed fluorescence (LQDF). The using of this phenomenon will greatly simplify the determination of the radiation “dose” in photodynamic therapy directly during the treatment session. Statistically certain distinction between delayed fluorescence characterization as well as LQDF extent in healthy and pathological tissues was established.