Systematic errors in displacement measurements performed using CT scannograms

Abstract

Computed tomography (CT) scan projection radiographs, or scannograms, are used increasingly to make distance measurements for pelvimetry purposes. A request was received from a local X-ray Department to investigate the efficacy of this method prior to clinical use. One of the factors investigated was the accuracy of cursor measurements in the direction of movement of the couch and transversely across the fan beam. Cursor accuracy was assessed using the method described by Wade [1].