Characteristics Of Three-dimensional Autofluorescence Of Human Nasopharyngeal Tissues In Vitro

The current status for clinical diagnostic approaches of nasopharyngeal carcinomawas presented. Light-induced autofluorescence technique seeks high sensitive, minimallyinvasive in situ, rapid for identification of normal and cancerous tissues on real time. Inthis thesis, three-dimensional autofluorescence spectra were performed to investigate thecharacteristics of human nasopharyngeal tissues in vitro. The obtained results provide animportant reference for determining the optimal excitation wavelengths for identifying thenormal and cancerous nasopharyngeal tissue in diagnostic applications.Firstly, the limitations of current approaches for the diagnosis of nasopharyngealcarcinoma were briefly discussed, and the investigation of light-induced autofluorescencewas proposed as a high sensitive method for detection of human nasopharyngealcarcinoma.Secondly, the autofluorescence characteristics of different endogenous fluorophoresin biological tissues were presented in detailed. The three-dimensional fluorescencespectra were firstly applied to the diagnosis of nasopharyngeal carcinoma.Finally, the characteristics of three-dimensional fluorescence spectra of humannasopharyngeal tissues were studied. The obtained results show that the primaryendogenous fluorophores in human nasopharyngeal tissues were the ceroid, amino acids,collagen, reduced nicotinamide adenine dinucleotide or reduced nicotinamide adeninedinucleotide phosphate, and flavin adenine dinucleotide, respectively. Based on thepathological and morphological results, the difference of 3-D autofluorescence spectrabetween normal and cancerous nasopharyngeal tissues were comparatively studied.Furthermore, the experimental results indicate that the affection of the illumination andcollection geometry for biological tissues, as well as the blood on the intensity oflight-induced aufluorescence is more significant than the photobleaching of endogenousfluorophores. Finally, the optimal excitation wavelength for the diagnosis of discriminationnasopharyngeal tissues was determined at about 340 nm.