Abstract
We developed a new endoscopic system capable of measuring the 3 dimensional structure of gastric lesion. The system consists of a low power argon laser, a side-viewing endoscope with transmission diffraction grating made of double layer glass fiber, and a graphic processing unit with 16 bit CPU microcomputer. Via fiber grating at the top of the endoscope, about 600 dots of the diffracted laser beam were projected clearly on the gastric lesion. By graphic processing for detecting deviation of laser spot array on the lesion, the diameter, area and the height of the lesion were determined. For evaluating the accuracy of the system to measure the diameter and area, a rubber disc 20mm in diameter was determined in vitro and in the stomach. Aberration ratio for measuring the diameter and area of the disc in the stomach were very small. There were no statistically significant difference between the, four determinating conditions, with direct angle of view, oblique view, in vitro and in the stomach (Table 1, 2, 4, 5). The height of a cubic lesion model 9.8mm in height, photographed under direct view, was measured. The aberration ratio for determinating the height was 9.2 + 2.1%. To measure the height and depth in the stomach, a new graphic processing technique, the axis co-ordinate rotation, was necessary. The new graphic processing program was made and will be reported in the near future. The system is the first device capable of measuring the height and depth of the gastric lesion endo-scopically. The system is useful to study the healing process of gastric ulcer, to evaluate the effect of antiulcer drugs, and also should become a tool for a new diagnostic approach to early gastric cancer.
