Calibration of C-arm for orthopedic interventions via statistical model-based distortion correction and robust phantom detection

In this paper, we present a novel C-arm calibration approach for orthopedic applications that is based on a distortion correction plate with fiducials arranged in a single-plane and a novel mobile phantom. The former is designed to be rigidly attached to the image intensifier and is used together with a statistical model of the geometrical image distortion pattern for intra-operative image distortion correction. The latter can be placed to anywhere close to the patient anatomy being imaged. A simulation based method is then proposed for a robust detection of the phantom from an intra-operatively acquired image in order to compute both the intrinsic and the extrinsic parameters of the acquired image. Validation study performed on 20 cadaver images demonstrated an average calibration accuracy of 0.8 ± 0.4 mm.