1. A tomographic system comprising: a gantry having an opening for receiving an object to be scanned; a radiation source; a detector positioned to receive radiation from the source that passes through the object; and a computer programmed to: acquire a plurality of projection datasets of the object; define a temporal subset of projection datasets from the plurality of projection datasets; reconstruct a working image of the object using the plurality of projection datasets; identify a region of motion in the working image; and minimize motion artifacts in the region of motion in the working image using the temporal subset of projection datasets.