JPS54160194A - Ct scanner - Google Patents

Abstract

PURPOSE: To secure corection of the increment of the slice width at the fringe area caused by the central radiant rays of the fan beam by decreasing the beam thickness at the fringe area, and thus to ensure the substantial uniformity for the slice width.

CONSTITUTION: Fan beam 16a radiated from radiation source 14 transmits through tested object 15 and enters the detector. in this case, the radiant rays at center part 19 of beam 16a always pass through the center part of the fault surface to contribute to the whole fualt surface, but the radiant rays at fringe part 20 contribute only to the circumference part of the fault surface. As a result, the cross-section of the fault surface becomes thin at the center part and thick at the fringe part owing mainly to the radiant rays at the center part. This can be corrected by decreasing the deflecting width and thickness of beam 16a gradually from the center to fringe part. As a result, the thickness of the fan beam can be changed uniform substantially, and accordingly the pickup leak part can be solved in the case of the continuous shooting of several slices. And furthermore, the double exposure can be reduced.

COPYRIGHT: (C)1979,JPO&Japio