Study On Laser Induced Autofluorescence Of Plasm For Stomach Cancer Diagnosis

More and more people pay attention to the effective cancer identification method which is significant to save cancer patients'lives. Fluorescence spectroscopy was paid attention to, for its advantages of real time detection, impersonality innocuity and so on. Although the cancer identification using spectroscopy has been studied extensively, it is still at its primary stage. Especially the slow spectrum analysis technology has kept back the development of fluorescence spectrum for stomach cancer diagnosis.Laser induced fluorescence(LIF) system was set up in the thesis. 45 pieces of autoluorescence of plasm were measured by means of fluorescence spectrophotometer and LIF system. 405nm was chosen as excitation wavelength. The partial Least-squares based on the artificial neural network(PLS -ANN) was used to analyze the second derivative spectra. The sensitivity, the specificity and the success rate of two systems are separately 86%,96%,93%;95%,100%,98%. So it's concluded that the second method which was measured by LIF using the PLS-ANN to analyzing spectra was more effective for identification of stomach cancer. On the other hand, a rapid, sensitive and reproducible high performance liquid chromatography(HPLC) method was used to analyze porphyrin IX in human plasm, with fluorescence detection at 628nm(excited at 404nm). It was found that the concentration of porphyrin IX in cancer was 4.6534x10^-5-18x10^-5μg/μl while it was 1.0485 x10^-5-1.9352x10^-5μg/μl in normal plasm.