Fast Streaking Artifact Reduction in CT Using Constrained Optimization in Metal Masks

Here we accelerate computations that reduce CT metal artifacts by observing that metal projects to only a fraction of the X-ray detectors in each projection, and thus computations should focus on these metal “mask” regions. We propose that the penalized maximum likelihood optimization method for artifact reduction needs to be solved only within the metal mask, using the remaining non-mask regions as a constraint; we show that our approach leads to a 10x speedup.