high performance computing on graphics processing units: hgpu.org

Iterative CT algorithms have become increasingly popular in recent years. They have been found useful when the projections are limited in number, irregularly spaced, or noisy, which are often encountered in low-dose CT imaging. One way to cope with the associated streak and noise artifacts is to interleave a regularization objective into the iterative reconstruction framework. In this paper we investigate a number of non-linear neighborhood filters within an iterative CT framework, OS-SIRT, and compare them with total variation minimization (TVM). We find that the Non-Local Means (NLM) filter provides the best performance, in particular its patch-based variant. Further, we also compare a scheme that exploits an artifact-free reference image for even better regularization performance. Finally, we also compare the studied filters in terms of their computational efficiency with acceleration on modern GPUs.