Metal artifact reduction in CT-based attenuation correction of PET using sobolev sinogram restoration

A. Mehranian, M. R. Ay, A. Rahmim, H. Zaidi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In patients bearing metallic implants, CT images reconstructed by the filtered back-projection algorithm usually suffer substantially from streaking metal artifacts. The CT-based attenuation correction of PET using such images can lead to pseudo-uptakes and thus equivocal findings. In this paper, we introduce a new metal artifact reduction (MAR) algorithm based on Bayesian iterative restoration techniques applied in the sinogram space. We proposed a Sobolev prior in the maximum a posteriori (MAP) estimation of the projections corrupted by metallic implants. The Sobolev prior was invoked in order to impose the a priori knowledge that a CT sinogram is a smooth dataset in which it is highly probable that neighboring projections have similar photon counts. We compared the proposed prior with a total variation (TV) one which imposes piece-wise smoothness on the sinograms being restored. We also compared it with a smoothed TV (TVs) prior which ranks between the Sobolev and TV ones. We formulated the MAP estimation as a convex constrained optimization problem and solved it for the Sobolev and TVs priors by a projected gradient descent algorithm and for the TV/s priors by a sophisticated primal-dual projected gradient algorithm. The results of artifact simulations in a real CT image showed that the Sobolev-based MAR algorithm outperforms its TV and TVs-based counterparts in terms of convergence rate and is comparable with the TVs in projection recovery. It was demonstrated that the proposed MAR algorithm has high applicability in fast and efficient CT-based attenuation correction of PET data.

Original languageEnglish (US)
Title of host publication2011 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2011
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages2936-2942
Number of pages7
ISBN (Print)9781467301183
DOIs
StatePublished - 2011
Event2011 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2011 - Valencia, Spain
Duration: Oct 23 2011Oct 29 2011

Publication series

NameIEEE Nuclear Science Symposium Conference Record
ISSN (Print)1095-7863

Other

Other2011 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2011
Country/TerritorySpain
CityValencia
Period10/23/1110/29/11

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging

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