Patent ID: 7020317

Claim:
A computed tomography apparatus comprising: a scanning unit which includes a radiation source (S) and a detector unit ( 16 ) which is connected thereto in order to detect a conical radiation beam, emitted by the radiation source, after its passage through an examination zone ( 13 ) or an object present therein; a drive device ( 2 , 5 ) for producing a relative motion in the form of a helix ( 17 ), consisting of a rotation about an axis of rotation ( 14 ) and an advance in the direction parallel to the axis of rotation, between the scanning unit (S, 16 ) and the examination zone ( 13 ) or the object, the helix and the detector unit being proportioned in such a manner that the detector unit simultaneously detects all rays of the radiation beam within a first measuring window whose edges ( 163 , 164 ), being offset relative to one another in the direction of the axis of rotation ( 14 ), are defined by lines which originate from the radiation source (S) and intersect two segments of the helix ( 17 ) which are offset over the distance (2n+1)p in the direction of the axis of rotation, where n is an integer number ≧1 and p corresponds to the axial offset of two neighboring turns of the helix; and a reconstruction unit ( 10 ) for reconstructing a CT image which corresponds to the spatial distribution of the absorption within the examination zone ( 13 ) from the measuring data acquired by the detector unit ( 16 ) within the first measuring window ( 160 ), the measuring data derived from rays which extend within a second window being assigned a weight for the reconstruction which differs from that assigned to the measuring data derived from rays which extend outside the second measuring window but inside the first measuring window, and the second window being situated, viewed in the direction of the axis of rotation, at the center of the first measuring window and its mutually offset edges ( 163 , 164 ) being defined by lines which originate from the radiation source (S) and intersect two segments of the helix ( 17 ) which are offset over the distance (2m+1)p in the direction of the axis of rotation, where m is an integer number and 0≦m≦n.