value and considering all voxels in which the associated grayscale values are above said threshold value as filled by metal in the present case the aim is to perform the segmentation in a plurality of stages the voxels accordingly being recorded initially as u201c seed points u201d with the aid of the threshold value criterion and moreover for a so called u201c connected threshold segmentation u201d in a connected threshold segmentation a lower and an upper range value are specified all voxels which are connected with the initially recorded voxels and in which the grayscale values lie in the cited value range between the lower and upper range values are added to the metal i e saved as a segmented volume region in the present case the aim is in particular also to adjust the parameters regionally which can be realized in a plurality of stages in the course of a segmentation the regional adjustment of such parameters for instance the lower and upper range value is known per se after a binary image in other words a 3d image dataset in which the individual voxels are assigned either a u201c 1 u201d or a u201c 0 u201d has thus been generated in step s 14 the aim is now to ensure that the excessive grayscale values are no longer present in the 2d image datasets i e the traces of the metal are to be eliminated accordingly the following steps as known per se from de 10 2007 016 319 a1 are performed for all focus positions for which a 2d.