Iterative volume of interest image reconstruction in helical cone beam X-Ray CT using a stored system matrix approach

Jingyan Xu, Benjamin M.W. Tsui

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

1 Scopus citations


We present an efficient scheme for the forward and backward projector implementation for helical cone-beam x-ray CT reconstruction using a pre-calculated and stored system matrix approach. Because of the symmetry of a helical source trajectory, it is sufficient to calculate and store the system matrix entries for one image slice only and for all source positions illuminating it. The system matrix entries for other image slices are copies of those stored values. In implementing an iterative image reconstruction method, the internal 3D image volume can be based on a non-Cartesian grid so that no system matrix interpolation is needed for the repeated forward and backward projection calculation. Using the proposed scheme, the memory requirement for the reconstruction of a full field-of-view of clinical scanners is manageable on current computing platforms. The same storage principle can be generalized and applied to iterative volume-of-interest image reconstruction for helical cone-beam CT. We demonstrate by both computer simulations and clinical patient data the speed and image quality of VOI image reconstruction using the proposed stored system matrix approach. We believe the proposed method may contribute to bringing iterative reconstruction to the clinical practice.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2011
Subtitle of host publicationPhysics of Medical Imaging
StatePublished - 2011
EventMedical Imaging 2011: Physics of Medical Imaging - Lake Buena Vista, FL, United States
Duration: Feb 13 2011Feb 17 2011

Publication series

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


OtherMedical Imaging 2011: Physics of Medical Imaging
Country/TerritoryUnited States
CityLake Buena Vista, FL


  • CT artifacts reduction
  • dose reduction
  • helical cone beam computed tomography
  • iterative image reconstruction

ASJC Scopus subject areas

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


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