Patent ID: 6744844
Filing Date: 2004-06-01
Classification: A61B,G01N,G06T,Y10S

Abstract:
An X-ray CT apparatus comprising:an X-ray tube; a multi-row detector having more than one detector row opposed to said X-ray tube; a translation control device for translating said X-ray tube and said multi-row detector along an axis of translation relative to a subject; a rotation control device for rotating at least one of said X-ray tube and said multi-row detector around an axis of rotation, a tilt control device for tilting the angle of a scan plane formed by said rotation relative to the axis of translation to an angle other than 90Â°, a scan control device for collecting data by a helical scan employing said multi-row detector with the scan plane tilted; an image producing device for producing an image based on the collected data; and a tilt correcting processing device for applying to the data tilt correcting processing for correcting view-to-view variation of the positions of channels in the detector rows relative to the axis of translation due to the tilt of the scan plane, wherein said tilt correcting processing device comprises: a data extracting device for extracting data from a (Roundup{Lj* tan &thgr;/DMM}+1+j_delt_iso)-th channel to a (Iâ€”Roundup{Lj* tan &thgr;/DMM}âˆ’1+j_delt_iso)-th channel in a j-th (j is the detector row index and 1&lE;j&lE;J) detector row for a pvn-th view, where pvn is the view index and 1&lE;pvn&lE;VWN, rotation is made substantially for 2&pgr; for all views, the tilt angle is represented as &thgr;, a distance from an intersection of the axis of translation and the axis of rotation to a scan plane corresponding to the j-th detector row is represented as Lj, DMM is the channel-to-channel distance, Roundup { } is a roundup function, and jâ€”deltâ€”iso=Lj* tan &thgr;* sin{2&pgr;(pvnâˆ’1)/VWN}a dummy data appending device for appending the extracted data with dummy data to adjust the data range; and a data transformation device for transforming the data into data enabling alignment of the channel positions through all views.