Implementation of an effective KL domain penalized weighted leastsquares sinogram restoration for low-dose CT colonography

Yi Fan, Jing Wang, Hongbing Lu, Zhengrong Liang

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

1 Scopus citations


Currently available spiral/helical computed tomography (HCT) technologies have demonstrated the potential for CTbased virtual colonoscopy or CT-colonography (CTC). However, a major limitation for this clinical application is associated with the risk of high radiation exposure, especially for its use for screening purpose at a large population. In this work, we presented an improved Karhunen-Loeve (KL) domain penalized weighted least-squares (PWLS) strategy which considers the data correlation among the nearby angular views and nearby axial slices simultaneously so that a fully three-dimensional (3D) restoration problem can be reduced to a 1D operation and therefore an analytical calculation is feasible for highest computing efficiency. The KL-PWLS strategy was implemented and tested on computer simulated sinograms which mimic low-dose CT scans at different noise levels characterized by 50, 40, 30, 20 and 10 mAs respectively. The reconstructed images by the presented strategy demonstrated the potential of ultra low-dose CT at as low as 10 mAs for VC application. Further evaluation by receiver operating characteristic study is needed and is under progress.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2009
Subtitle of host publicationPhysics of Medical Imaging
StatePublished - 2009
EventMedical Imaging 2009: Physics of Medical Imaging - Lake Buena Vista, FL, United States
Duration: Feb 9 2009Feb 12 2009

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherMedical Imaging 2009: Physics of Medical Imaging
Country/TerritoryUnited States
CityLake Buena Vista, FL


  • Adaptive noise treatment
  • Karhunen-Loeve transform
  • Low-dose computed tomography
  • Noise reduction
  • Penalized weighted leastsquares

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging


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