Fiber Raman Spectroscopy System For Diagnosis Of Early Gastric Cancer And Stomach Cancer

BackgroundGastric cancer is the third leading cause of cancer deaths globally,with high incidence and mortality rates in China.It is estimated that the number of deaths from stomach cancer accounts for nearly half of the global annual death toll from that each year in China.As population growth and aging,cancer of the stomach will result in heavy social and economic burden,and may trigger a major public health problem.At present,the gastric cancer diagnosis mainly depends on the gastroscope biopsy.Because of the lack of specificity and operators subjective factors,Accuracy of early diagnosis of gastric cancer is not high,especially in multifocal stomach and after ESD treatment,leading some patients developping to advanced gastric cancer and losing the chance of resection.Targeted biopsies of stomach cancer are usually time-consuming,invasive and performed under general anesthesia,easily causing complications such as bleeding,infection,choking cough.Raman spectroscopy is a kind of inelastic scattering spectroscopy based on molecular vibrations,which can provide specific information of structure and composition of tissue.Cancerous tissue can provide characteristic Raman spectra due to its composition content,structural changes.Because of rapid,noninvasive,objective and highly accurate characteristics and without pretreatment of tissue samples,Raman spectroscopy is very suitable for the combination with endoscopic examination for the diagnosis of gastric cancer and to guide the endoscopic treatment of gastric cancer.ObjectiveThe purpose of the study is to develop a optical fiber Raman system matching the gastroscopy.Using it,we could carry out Raman spectroscopy for gastric cancer diagnosis research in vitro or in vivo and looking for efficiently diagnostic index.MethodPart Ⅰ:We used this system to collected 83 spectrum from 29 patients with biopsy examination,including 17 patients with gastric carcinoma and 12 patients with normal gastric mucosa（excitation wavelength of 785 nm light,power of 50 mw,the CCD temperature to 80℃,acquisition time 1 s）under the condition of the dark.Raman spectrum and the ratio of integral energy from continuous band(1500-1700cm^-1)and non-continuous band(1100-1200cm^-1)were compared.Part Ⅱ:We set up the fiber Raman spectroscopy system with the same parameters used in vitro.Patients were examined by Raman spectroscopy Combined with ME-NBI,including 14 cases of normal mucosa,13 cases of high level intraepithelial adenoma.Then we compared Raman spectrum and the ratio of integral energy from1500-1600cm^-1and1600-1700cm^-1.ResultThe intensity of Raman peak of gastric adenocarcinoma at 1002 cm^-1、1073 cm^-1、1450cm^-1、1655cm^-1 Belonging to phenylalanine and proteins are higher than that of normal mucosal relatively.From continuous band(1500-1700cm^-1)and non-continuous band(1100-1200cm^-1),the ratios of the spectral integral energy of gastric adenocarcinoma were different with normal mucosa markedly（independent samples t test,P<0.05）,and with the ratio of the integral energy for use as a diagnostic index,obtained the higher accuracy（97.5-98.5%）,sensitivity（91.7%）and specific degrees（100.0%）.Using the same set of system in the body to test normal gastric mucosa and high level intraepithelial neoplasia,we found that new proteins and amino acids might be synthetized,polysaccharides and lipids decreased at the same time in cancerous cells.The ratios of the spectral integral energy of high level intraepithelial neoplasia were different with normal mucosa markedly（nonparametric test,P<0.001）,and with the ratio of the integral energy for use as a diagnostic index,obtained the higher accuracy（95.1%）,sensitivity（100%）and specific degrees（85.7%）.ConclusionFiber Raman spectroscopy system applied in the clinical diagnosis of gastric cancer had a high value.Fiber Raman spectroscopy system can not only provide information from cancerous gastric mucosa at the molecular level,but also can be compatible with gastroscopy to diagnoses early gastric cancer and stomach cancer in real-time.The ratio of the integral energy as the diagnostic indicator can effectively distinguish cancerous gastric mucosa from normal tissue.Fiber Raman spectroscopy technology has high value in clinical diagnosis.