A sinogram restoration technique for the hollow projection problem in computer tomography

This paper studies the hollow projection problem in computer tomography which occurs frequently in medical imaging, for example when the patient has a metal implant such as a hip-joint that attenuates the rays completely. Here, an interpolation method is presented to restore a complete sinogram from the available incomplete data. The algorithm is based on the Ludwig-Helgason Consistency Theorem and uses the edge values of the missing part of the incomplete sinogram. A computationally efficient algorithm is proposed to solve the interpolation problem. Computer simulation results demonstrate that the proposed method works well.