RECENT DEVELOPMENT AND USEFULNESS OF INFRARED ENDOSCOPIC SYSTEM FOR DIAGNOSIS OF GASTRIC CANCER

Background:  Near-infrared (IR) rays, because of their limited scattering characteristics and low absorption by water and hemoglobin, can penetrate deeply into tissue. Using infrared rays, we have developed an infrared electronic endoscope system and evaluated its usefulness for assessing the depth of involvement of gastric cancers. Recently, we developed a new infrared videoendoscopic system (dual wavelength system). With this system, we can recognize submucosal vessels of gastric cancers in a greater detail with higher resolution under IR light. Methods:  A total of 30 patients with depressed gastric cancers underwent infrared endoscopy. Results:  Twenty-one (91%) of 23 intramucosal and submucosal cancers less than 1000 µm were observed as tumors with no stain or faint stain, whereas all (100%) of seven more invasive cancers were observed as tumors with dense stain or pooling of the dye. Thus, the overall accuracy was 93% (28 of 30 tumors). Moreover, 95% (18 of 19) of tumors with ulcerative changes were correctly diagnosed. Conclusions:  New infrared electronic endoscopic system is useful for diagnosing the depth of involvement of early gastric cancer either with or without ulcerative changes. This system will bring us further development in the diagnosis of gastric cancer.