The Diagnostic Feature Of Gastric Cancer Based On Second Harmonic Generation And Two-Photon Excited Fluorescence

Many neoplasms occur in biological tissues with a fine stratified structure, and most of stomach cancers develop in the gastric mucosa. Due to poor diagnosis, the stomach cancer is the second most common cause of death. Multiphoton excitation microscopy (MPM) is an emerging nonlinear spectral imaging based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG). This microscopy combines two-photon excitation microscopy with spectral measurement technique, so it can be simultaneously used for obtaining tissue image and spectra at different depth. In this thesis, firstly, combining TPEF and SHG, the lamina propria of normal human gastric mucosa was observed. Our results demonstrated that MPM can be very effective to characterize the microstructure of lamina propria in normal human gastric mucosa. Then, by using MPM, the mucosa and submucosa of human normal and cancerous gastric tissues were investigated, and the diagnostic features for identifying the two layers were established. Our findings show that MPM can be capable of exhibiting the mucosal and submucosal microstructures of normal and cancerous gastric tissues, as well as the distribution and content of abnormal cells in the two layers. More importantly, the results can provide the groundwork for establishing clinical diagnostic criteria of gastric cancer. In a word, our findings suggested that MPM has great potential for providing more accurate and comprehensive information in physiological analysis and pathological diagnosis of human gastric tissue. With the development of clinically miniaturized MPM and multiphoton probe, our results can be helpful for applying multiphoton endoscopy to perform real-time in vivo early diagnosis of gastric cancer.