Method of detection and correction of image distortions in medical imaging

摘要

Distortion in computer tomography pictures may arise from calibration errors, deviation in the speed of movement of the patient's couch or bending of the couch due to the patient's weight. These distortions can be corrected by use of a phantom body (14) connected to the patient's couch (5) in the area to be X-rayed. This is X-rayed in several layers to build up a complete CT picture at the same time as the patient. The phantom body consists of two X frames (20,21) fixed to one another (141), one of which is vertical to the plane of the layers of the picture, or of N-shaped frames. Picture coordination on at least five points of the phantom picture is determined and used to direct coordination of the corresponding points in a corrector.