Patent ID: 7085345

Claim:
A radiation computed tomographic imaging apparatus comprising: a radiation source for emitting radiation while rotating around a predefined axis of rotation, wherein said radiation source has an X-ray focal spot; a radiation detector for detecting said radiation passing through a subject around said axis of rotation, said radiation detector having a plurality of radiation detector elements for detecting said radiation, extending in a two-dimensional manner in first and second arrangement directions, said first arrangement direction being contained in a plane of rotation of said radiation source, said second arrangement direction being orthogonal to said first arrangement direction and aligned along said axis of rotation; and a reconstructing device for arithmetically reconstructing tomographic image data for a tomographic image of said subject based on projection data of said subject obtained from said radiation detected by said radiation detector, wherein said radiation detector comprises collimators for confining an angle at which said radiation impinges upon said radiation detector elements, said collimators being provided at borders between said radiation detector elements adjoining in said second arrangement direction, and wherein a first one of said collimators has a first height determined based on a drift of said X-ray focal spot.