| Summary: | 碩士 === 國立中正大學 === 物理學系暨研究所 === 101 === Photodynamic therapy (PDT), as a cancer or malignant neoplasm treatment, is one of the emerging therapies which can accomplish the purpose of detection and treatment simultaneously. Up to this moment, PDT is highly evaluated because it, unlike other therapies, does not demand extra detective steps to locate the deadly cells.
PDT includes three key components: light, photosensitizers and oxygen molecules (O2). By photo-excitation of the photosensitizers, smeared or intravenously injected to the malignant tissue, the surrounding O2 are activated or even converted into cytotoxic radicals, by inter-molecular excess energy transfer, to facilitate apoptosis and necrosis in the malignant cells. Since no surgery is needed, PDT is referred to as a non-invasive treatment. In the apoptosis and necrosis processes, the active oxygen or cytotoxic radicals initiate oxidation reaction with the DNA, proteins, and lipid substance in cancer cells. However, it is unlikely to hurt any other normal cells.
We have previously measured the lifetime of singlet oxygen promoted to the first excited singlet state by the solutions of Hematoporphyrin dissolved in acetone, 5,10,15,20-Tetrakis (1-methyl-4-pyridinio) porphyrin tetra (p-toluenesulfonate) dissolved in heavy water and Rose Bengal dissolved in heavy water. In this thesis, we measured the cell viabilities after the cells were added with photosensitizers and divided into two highly similar samples, referred to experimental and contrast samples respectively. We respectively conducted the viability measurements on the experimental samples with illumination at proper wavelengths and on the corresponding contrast samples without illumination. Note that sodium light was used in this study as the light sources. By comparing the amount of surviving cells in these two samples, both normalized with the surviving cells of another unilluminated sample with pure cells alone, we determined the viability of the PDT treatment with the specific photosensitizers. Note that although photosensitizers used in this thesis were the same as those used before, all of the solvents were different. In addition, according to our study, cells may be killed by some photosensitizers without illumination.
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