US Patent 7260175 CT image producing method and X-ray CT apparatus

A method for producing a CT image by applying Z-filtering to axial scan data collected using a multi-row detector, wherein second axial scan data is collected at a second position Z2 to which an X-ray tube and a multi-row detector are rectilinearly moved relative to a subject to be imaged from a first position Z1 toward an end of the multi-row detector, projection data corresponding to a central portion a2 of a reconstruction field P3 near the end of the multi-row detector is extracted from the second axial scan data, and Z-filtering is applied based on the projection data of reconstruction fields P1, P2 and P3 to produce one CT image.