CT APPARATUS HAVING X-RAY IRRADIATING DIRECTION AND DETECTOR ORIENTATION SET IN ARBITRARY DIRECTIONS, AND THREE-DIMENSIONAL IMAGE RECONSTITUTING METHOD AND PROGRAM FOR THE APPARATUS

摘要

Provided are an X-ray CT apparatus, in which an X-ray irradiating direction (i.e., a direction of a half straight line starting from an X-ray focal point and joining the X-ray focal point and the rotational center point of an object) is set to an arbitrary direction and in which a detector is also arranged in an arbitrary direction, and a three-dimensional image reconstituting method for the apparatus. The CT image reconstituting method for changing the object into a three-dimensional image comprises (1) the step of preparing the X-ray CT apparatus having a detecting plane arranged for detecting an X-ray having passed through an object arranged at a predetermined distance with respect to an X-ray source, (2) the step of orienting the arrangement of the detecting plane of the detector in an arbitrary direction with respect to the straight line joining the X-ray source and the object, (3) the step of detecting irradiating the object with the X-ray at an angle larger than 0 degrees in the rotating direction thereby to detect the projection image data with the detector, and (4) the step of performing an image reconstitution from the projection image data detected, to display the internal structure of the object three-dimensionally. The CT image reconstituting method is characterized by performing the operations (A) to apply a predetermined weight to the projection image data, (B) to filter the weighted projection image data, and (C) to project the filtered data inversely by a predetermined method in a three-dimensional reconstituting space.