System matrix for OSEM SPECT with attenuation compensation in mesh domain

Levon Vogelsang, Andrzej Krol, David H. Feiglin, Edward Lipson

Research output: Chapter in Book/Entry/PoemConference contribution


The purpose of this study was to develop and implement an accurate and computationally efficient method for determination of the mesh-domain system matrix including attenuation compensation for Ordered Subsets Expectation Maximization (OSEM) Single Photon Emission Computed Tomography (SPECT). The mesh-domain system matrix elements were estimated by first partitioning the object domain into strips parallel to detector face and with width not exceeding the size of a detector unit. This was followed by approximating the integration over the strip/mesh-element union. This approximation is product of: (i) strip width, (ii) intersection length of a ray central to strip with a mesh element, and (iii) the response and expansion function evaluated at midpoint of the intersection length. Reconstruction was performed using OSEM without regularization and with exact knowledge of the attenuation map. The method was evaluated using synthetic SPECT data generated using SIMIND Monte Carlo simulation software. Comparative quantitative and qualitative analysis included: bias, variance, standard deviation and line-profiles within three different regions of interest. We found that no more than two divisions per detector bin were needed for good quality reconstructed images when using a high resolution mesh.

Original languageEnglish (US)
Title of host publicationMedical Imaging 2010
Subtitle of host publicationPhysics of Medical Imaging
EditionPART 3
StatePublished - 2010
EventMedical Imaging 2010: Physics of Medical Imaging - San Diego, CA, United States
Duration: Feb 15 2010Feb 18 2010

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
NumberPART 3
ISSN (Print)1605-7422


OtherMedical Imaging 2010: Physics of Medical Imaging
Country/TerritoryUnited States
CitySan Diego, CA


  • Attenuation compensation
  • Mesh domain
  • OSEM
  • Reconstruction
  • System matrix

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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