Abstract
A New Method to determine the area of gastric ulcer endoscopically without complex procedure was invented. A rubber disk, 5mm in diameter, was used as a marker. And a round object, 25mm in diameter was designed as the ulcer model. The marker disk was set in the center of a round object similar to a gastric ulcer. This model was photographed at various LOD ("Lens Object Distance"), from 1 to 5cm, in difference of every 2.5mm consecutively. We used more precise apparatus to measure the LOD than previous experiment, so the value in that report is corrected. At first, the ratio of the object to marker area were calculated on the picture enlarged to the cabinet size photographes. An aberration ratio was less than 10% by using the GIF-P2 and P3 type endoscopes with LOD over 4cm and by GTF-B100 type endoscope with LOD over 3cm. The precise area of the object disk was then calculated without correcting the optical distortion (Table 1, 2, 3). Secondarily, in order to correct the optical distortion of the f iberscope, a transparent board traced with the endoscopic photograph of squares in the same LOD was employed in measurement in less than 3cm of LOD if the GTF-B100 type endoscope was used and in less than 4cm of LOD if the GIF-P2 and P3 type endoscopes were used (Table 4). By use of these transparent boards, aberration ratio was corrected to less than 10%. Therefore, it became possible to determine the precise area of the object disk endoscopically even in short LOD. The transparent boards were copied to glass plates so that the diameter of the visual field is made the same as the diameter of visual field of the endoscopic film. The measurement of the ulcer is simplified by mounting the glass plate directly on the endoscopic film.
