THE SPECTROSCOPIC STUDY FOR MECHANISM OF PHOTO-RADIATIVE THERAPY
-THE GENERATION OF SINGLET OXYGEN AD THE ANALYSIS OF ITS DYNAMICAL PROCESS-
1987 Volume 8 Issue 2 Pages 53-67
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1987 Volume 8 Issue 2 Pages 53-67
Clinically, the photoradiative therapy by using laser radiation has been established as therapeutic method to cancer, but its fundamental theory of phototoxic has not been proved experimentally yet today. Since the 1970's, the energy transfer model from porphyrin to oxygen molecule has been advocated by Dougherty's group and singlet oxygen which was produced in this process has been regarded as the most important facer for photoradiative effect.
In this reports, we made use of picosecond pulse Nd: YAG laser system for light source and measured life times of red fluorescences (wave length=630nm) from porphyrin and of infrared fluorescences from singlet oxygen (wave th=1.27μm) in various porphyrin solutions.
Further more, for studying productive rate of singlet oxygen quantitatively, we analyzed temporal change of fluorescence in each process and calculate energy transfer rate from porphyrin to oxygen molecule by solving rate equation.
In this results, the ratio of energy transfer which was given to oxygen molecule was only less than 10-2-10-3. So the majority of first exited energy was transformed to other process beside oxygen molecule. We considered this other process from two different view point, one was the nonradiative process in porphyrin molecule and the other was the reabsorption of energy by solvent.
Thus, we must reflect other facer to make clear the fundamental each of photoradiative effect, but we think it is also important to confirm the production of singlet oxygen because there is possibility to destruct living body in small amount of singlet oxygen.
