A method for delineating a metal object for artifact reduction in tomography images is provided. Projection images of a body containing the metal object are received and a volume model of the body is formed on the basis of the projection images. Voxels that are part of a region encompassing the metal object and at least one metal artifact are chosen in the volume model on the basis of segmentation criterion and combined to form a first volume mask. The first volume mask is projected onto the projection images and a respective projection mask is generated. The projection masks are is altered on the basis of pixel values of the projection images. A second volume mask is determined from the altered projection masks. The second volume mask is altered on the basis of voxel values of the volume model and the altered volume mask is supplied as a description of the metal object.
