Tomographic projection data is segmented spatially by forming segmentation masks over the full outlines of objects appearing in isolation within selected data frame images. Further processing locates the object outlines in other data frames. Predictable effects of attenuation are used to attribute appropriate amounts of intensity to the segmented object space. Separate image reconstructions can be made of the segmented object data and the remaining projection data to independently optimize the reconstructions. Composite images can be made of the separate reconstructions.