Hematoporphyrin derivative (HPD) is retained by malignant tumors and emits fluorescence with peaks of 630 and 690 nm wavelength when HPD is exposed to light. It is therefore theoretically possible to make a diagnosis of malignant tumors by detecting the fluorescence of HPD. The authors developed a spectroscope system compatible with fiberoptic endoscopes to analyze the shape of the fluorescence light spectrum. We could clearly recognize the HPD-specific fluorescence in human cancer foci. This system can be applied to the measurement of the relative amount of HPD absorbed in superficial tumor tissue before the photodynamic therapy. This might suggest the extent of tumor. The clinical diagnostic applications of this system are described in this study.
By using a highly sensitive streak-camera technique, we investigate incorporation processes of HpD into malignant tumor m-KSA cells in vitro. The picosecond decays of the total fluorescence spectra, the wavelength-resolved fluorescence decays and the time-resolved fluorescence spectra from HpD in the cells are measured as a function of the incubation time. The results show that the aggregate component of HpD which has a fast fluorescence lifetime of 100 ps and a red-shifted band of -660 nm selectively accumulates more and more in the cells with the increase of the incubation time.Photobiol. 39, 851-859.
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