X-RAY CT APPARATUS, METHOD FOR CHANGING HELICAL PITCH, IMAGE RECONSTRUCTION PROCESSING APPARATUS, IMAGE RECONSTRUCTION PROCESSING METHOD, AND IMAGE RECONSTRUCTION PROCESSING PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a technique which enables reconstruction of a highly precise image effective for utilization for diagnosis, and which can reduce a dosage.;SOLUTION: This X-ray CT apparatus is equipped with a reconstruction means for reconstructing a pre-scanned image of a subject to be examined from X-ray transmission data based on pre-scanning, and for reconstructing a main-scanned image of the subject from X-ray transmission data based on main scanning; a judging means for judging the start of the main scanning on the basis of a change in the CT value of the pre-scanned image; and a scanning controlling means for performing the main scanning, while changing a helical pitch toward the terminal end of a direct image reconstruction area from a stopped position of a bed by the pre-scanning, on the basis of the result of judging by the judging means. The scanning controlling means starts the main scanning at the starting end of the image reconstruction range with a first helical pitch enabling the application of X-rays equivalent to a predetermined number of views, and continues the main scanning by changing the first helical pitch to a second predetermined helical pitch, after the application of the X-rays equivalent to the predetermined number of views.;COPYRIGHT: (C)2008,JPO&INPIT