CALIBRATION METHOD FOR RING ARTIFACT CORRECTION IN NON-IDEAL ISOCENTRIC 3D ROTATIONAL X-RAY SCANNER SYSTEMS USING A CALIBRATION PHANTOM BASED ROTATION CENTER FINDING ALGORITHM

摘要

The present invention refers to 3D rotational X-ray imaging systems for use in computed tomography (CT) and, more particularly, to a fast, accurate and mathematically robust calibration method for determining the effective center of rotation ( , ) in not perfectly isocentric 3D rotational C-arm systems and eliminating substantially circular ring artifacts (RA) which arise when using such a CT scanner system for acquiring a set of 2D projection images of an object of interest to be three-dimensionally reconstructed. For this purpose, a C-arm based rotational CT scanner comprising at least one radiation detector (D) having an X-radiation sensitive surface exposed to an X-ray beam emitted by at least one X-ray tube (S), each rotating along a non-ideal circular trajectory (TF, TCD) about an object of interest to be three-dimensionally reconstructed from a set of