A method for obtaining a Computer Tomography (CT) image of an object reduces heel effect artefacts and includes generating x-rays using an x-ray source comprising an angled anode, recording at least one set of 2D projections of the object or a part thereof, and generating at least one 3D CT image of the object. Each 3D CT image is corrected, wherein scaling factors for slices of voxels are determined with at least one 3D CT calibration image that pictures similar or identical object structures of a calibration object placed within the x-ray beam path with respect to a y-direction. A contribution to grey values of voxels belonging to said object structures attributable to the slice position in the y direction is determined at least approximately, and the scaling factor for a respective slice of voxels is chosen such that it compensates for the determined grey value contribution for that slice.