Preliminary Study Of Early Cancer Screening By Porphyrin Fluorescence In Blood

There are three major advantages of fluorescence spectroscopy over other spectral methods: high sensitivity, high speed, and high selectivity. Recently it has been used broadly in the field of cancer diagnosis. The dissertation focuses on the studies of rapid diagnosis of early cancer by fluorescence. Serum samples were extracted with ethanol on simple processing, combined with derivative technique, a rapid fluorescence method was established to determine the value of protoporphyrin DC in serum and applied to diagnose cancer at early stage; With whole blood samples prepared without any processing, the thin liquid cuvette and the front-surface technique, a direct fluorescence method was brought forward to detect protoporphyrin IX and zinc protoporphyrin in the whole blood and was used in the diagnosis of cancer at early stage. The dissertation is composed of following parts:In the first chapter, the literature was summarized. The clinical methods of tumor diagnosis and the application and development of fluorescence technique in the diagnosis of tumor were introduced. The application and development of fluorescence spectrometry combined with derivative technique and front-surface technology were reviewed. The profile of protoporphyrin IX as biomarker and the determination of porphyrins were also summarized. The plan of dissertation was put forward at the last part of this chapter.In the second chapter, Vistar big mice were inoculated with sarcoma to simulate cancer in human. The autofluorescence of protoporphyrin IX extracted from serum with ethanol was used to identify normal and early cancer samples. In combination with derivative technique, a rapid derivative fluorescence method could be achieved to diagnose cancer at the early stage. Simple pre-treatment was used in this method, and the operation was simple, rapid and inexpensive. The method had been applied to identify twenty normal and ten early cancer samples. No false negative sample was found in all ten cancer samples, and only one sample was false positive in normal samples. According to the statistical analysis done with t-test, the significant difference between healthy and early cancer samples is well established.In the third chapter, a direct front-surface fluorescence method was proposed for the first time to diagnose cancer at early stage by whole blood. SD mice were inoculated with sarcoma to simulate cancer in human. The whole blood was prepared without any treatment and was directly scanned by the front-surface fluorescence to determine protoporphyrin IX and zinc protoporphyrin values. And then their fluorescence intensity ratios were used as a basis for screening early cancer. Though the normal and early cancer samples could not be absolutely distinguished, according to the experiments and data, the significant difference between healthy and early cancer samples were obtained. The method improved by further study is expected for the screening of malignant tumors at early stage.