スパイラルCTを用いた三次元管腔表示の形状再現性に影響する諸因子について

抄録

We have evaluated the accuracy of three-dimensional endoscopic images which were reconstructed with a double threshold shaded surface display. The factors examined are as follows: thickness of three-dimensional endoscopic images, specific artifacts of spiral CTs. We used a spiral CT(SIEMENS SOMATOM PLUS). In this study, we used a Full Scatter Water phantom which is used in radiation therapy, SPECT QA Test phantoms with an empty acrylic cylinder and a Funnel phantom. The thickness of the wall on three-dimensional endoscopic image was influenced by the function of reconstruction, the threshold and the partial volume effect. When the phantom with an empty acrylic cylinder was obliquely laid on the Z-axis, a regular spiral artifact could always be observed. This was the same as the artifact which appeared in clinical three-dimensional endoscopy. This artifact was changed by collimation and table speed. If we take these three factors into consideration which influence the thickness of the wall on a three-dimensional endoscopic image and choose the least possible collimation and table feed, it is possible to improve the accuracy of three-dimensional endoscopic imaging.