Validation of the 4D NCAT simulation tools for use in high-resolution x-ray CT research

W. P. Segars, M. Mahesh, T. Beck, E. C. Frey, B. M.W. Tsui

Research output: Contribution to journalConference article


We validate the computer-based simulation tools developed in our laboratory for use in high-resolution CT research. The 4D NURBS-based cardiac-torso (NCAT) phantom was developed to provide a realistic and flexible model of the human anatomy and physiology. Unlike current phantoms in CT, the 4D NCAT has the advantage, due to its design, that its organ shapes can be changed to realistically model anatomical variations and patient motion. To efficiently simulate high-resolution CT images, we developed a unique analytic projection algorithm (including scatter and quantum noise) to accurately calculate projections directly from the surface definition of the phantom given parameters defining the CT scanner and geometry. The projection data are reconstructed into CT images using algorithms developed in our laboratory. The 4D NCAT phantom contains a level of detail that is close to impossible to produce in a physical test object. We, therefore, validate our CT simulation tools and methods through a series of direct comparisons with data obtained experimentally using existing, simple physical phantoms at different doses and using different x-ray energy spectra. In each case, the first-order simulations were found to produce comparable results (<12%). We reason that since the simulations produced equivalent results using simple test objects, they should be able to do the same in more anatomically realistic conditions. We conclude that, with the ability to provide realistic simulated CT image data close to that from actual patients, the simulation tools developed in this work will have applications in a broad range of CT imaging research.

Original languageEnglish (US)
Article number94
Pages (from-to)828-834
Number of pages7
JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Issue numberII
StatePublished - Aug 25 2005
EventMedical Imaging 2005 - Physics of Medical Imaging - San Diego, CA, United States
Duration: Feb 13 2005Feb 15 2005


  • Computer Phantom
  • Medical Imaging Simulation
  • X-ray CT

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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