An X-ray computed tomography (=CT) apparatus (10) has a filter element (2) for attenuating an X-ray beam (1). The filter element (2) has a spatially varying X-ray absorption capability along a cross direction (y) which is perpendicular to both the beam axis (z) of the X-ray beam and to a rotation axis (x) of a gantry. The spatially varying X-ray absorption capability exhibits a maximum absorption along the cross direction (y) at a zero position (y0), wherein X-rays passing through the filter element (2) at the zero position (y0) intersect the rotation axis (x). The CT apparatus allows for further reduction of the radiation dose for an object to be investigated, while simultaneously retaining high image quality.
