<p>A method and apparatus for obtaining shadowgraph images suitable for use in computed tomography scanner apparatus for subject localization. A source (20) of radiation that orbits the subject during a normal computed tomography scan is fixed relative an array of radiation detectors (28). The subject is then moved in a direction generally perpendicular to the plane of source (20) and array (28) to obtain a first shadowgraph data set. The source (20) is then orbited a small amount and the subject is again moved relative the source (20) and detector array (28) to obtain a second shadowgraph set of data. The two sets of data are then interleaved to obtain a shadowgraph image having higher resolution than either the first or second shadowgraph.</p>
