Abstract
To establish one of endoscopic diagnostic procedures for gastrointestinal cancers, we developed a new laser instrument and evaluated it in detail. YAG laser was produced by laser system (Surgical Laser Technologies, Inc., Malvern, P. A.) and the wavelength of YAG laser was changed from 1, 064 nm (infrared) to 532nm (green) with KTP crystal and irradiated into pheophorbide solution and the fluorescence from pheophorbide was subject-ed to spectroanalysis with the high sensitvity spectrophotometer and the intensity of the each wavelength was measured with the photomultiplier. (Hamamatsu Photonics, Inc.) The fluorescence was seen in the range from 660nm to 800nm and showed the peak at 680nm. Studies of the relationships between the intensity of fluorescence and the holding voltage, density of pheophorbide, laser power, laser frequency, The distance between the fiber tip and the pheoporbide solution has revealed that the instrument can detect the very weak fluorescence and might be useful for the endoscopjc diagnosis of gastrointestinal cancers.
