| Theme |
The Latest Frontier of Endoscopy |
| Title |
Fluorescence Imaging Endoscopy |
| Author |
Tatsuo Ogihara |
Department of Gastroenterology, Juntendo University |
| Author |
Akihiro Namihisa |
Department of Gastroenterology, Juntendo University |
| Author |
Nobuhiro Sato |
Department of Gastroenterology, Juntendo University |
| [ Summary ] |
The autofluorescence of neoplastic tissue, irradiated by blue light, is known to be different from that of normal tissue. By applying this phenomenon, an auto-fluorescence imaging system using fiberoptic endoscopy was first developed for the detection of gastrointestinal neoplastic lesions. However, the fiberscope produces a low quality image compared to that produced with video endoscopy. Therefore, an autofluorescence imaging videoscope system was next developed. Auto-Fluorescence Imaging (AFI) video endoscopic systems are capable of displaying images on the monitor by switching to two modes ; one using conventional white light observation and one using autofluorescence observation. The AFI videoscope has two CCDs for producing images in the conventional mode and in the AFI mode. The CCD for conventional observation takes images from R, G and B reflected light based on a RGB sequential system irradiated by R / G / B wavelengths from a light source. In the AFI mode, the excitation light (395 - 475 nm) for taking autofluorescence images and the G'-light (550 nm) for taking reflected images irradiate based on a time-sharing system and the composite pseudocolor image is displayed on the monitor in a real time fashon. Endoscopic autofluorescence imaging systems, which need no administration of photosensitive agents, are considered to be useful in screening to detect and differentiate gastrointestinal neoplasms. |