Reducing short-scan artifacts in 3 D axial cone-beam CT with extra views

For 3D axial cone-beam CT, the short-scan approach has advantages, such as improved temporal resolution and lower dose, compared to the full-scan approach, due to significantly reduced data acquisition time. However, decreased angular span of the projections leads to insufficient sampling at certain voxel locations in third-generation CT geometries. Such sampling leads to artifacts in the reconstructed image, especially on slices away from the iso-plane. Using more projection views in the reconstruction can reduce such artifacts, but has the trade-off of decreased temporal resolution. This paper investigates a modelbased iterative reconstruction (MBIR) method that reduces shortscan artifacts in the under-sampled slices while preserving the temporal resolution in the well-sampled slices. Clinical cardiac scans typically include extra views for the purpose of viewing different phases, motion-compensation algorithms, etc.. Here we use such extra views to reduce short-scan artifacts in the undersampled region. Using XCAT phantom simulations, we investigated an approach to modifying the statistical weights associated with the extra views. This approach reduced shortscan artifacts, particularly in slices near the ends of the axial field-of view (FOV).