Cone beam artifact reduction in circular computed tomography

Cone beam artifact is a well known problem in circular computed tomography. The artifact can be removed by applying exact reconstruction, for example with circle and line trajectory. However, an additional scan often is not available for reconstruction, nor it is practical to collect. Then, methods that can accurately reconstruct image volume from circular data only are of particular interest. In this work we propose a new approach that combines elements of exact reconstruction and iterative reconstruction (SART). We apply iterative procedure to estimate missing line data; at each iteration line data becomes more accurate and cone beam artifacts are further reduced. Evaluation with numerical disc phantom and clinical head data shows effectiveness of the proposed approach in cone beam artifact reduction.