Metal artefacts such as streaks and shading in Carm cone beam CT (CBCT) scans are often not caused by "photon starvation", i.e. there is still information in the metal shadow. Instead, the artefacts are caused by inconsistent lineintegral measurements between different projections (e.g. lateral and anterior-posterior). These inconsistencies have two main causes: First, inconsistent removal of scatter or other imaging deficiencies for rather big static high-contrast objects like screws and metal hip implants. Second, motion inconsistencies for rather small moving high-contrast objects like contrast filled vessels or catheters.
A newly developed two-pass method based on the subtraction of the registered metal shadow that is filtered with a matched 2D filter is presented. Good results in the case of moving and static ’metal’ objects are achieved.