1. A method for determining a three-dimensional reconstruction of an examination object, comprising: determining a provisional three-dimensional reconstruction of the examination object based on a plurality of two-dimensional original projection images of the examination object; segmenting the provisional three-dimensional reconstruction to determined a provisional metal volume; mapping the provisional metal volume into the original projection images to create a plurality of corresponding provisional metal areas; defining edge zones of the provisional metal areas in the original projection images; selecting edge points from the edge zones; determining modified projection images by modifying data values of the original projection images assigned to locations in the provisional metal areas as a function of data values of the selected edge points; calculating differential images based on the original projection images and the corresponding modified projection images; segmenting the differential images to determine definitive metal areas; subtracting the definitive metal areas from the differential images; and determining the three-dimensional reconstruction by adding the subtracted differential images to the corresponding modified projection images.