Characterization of operating parameters of an in vivo micro CT system

Muhammad U. Ghani, Liqiang Ren, Kai Yang, Wei R. Chen, Xizeng Wu, Hong Liu

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

1 Scopus citations


The objective of this study was to characterize the operating parameters of an in-vivo micro CT system. In-plane spatial resolution, noise, geometric accuracy, CT number uniformity and linearity, and phase effects were evaluated using various phantoms. The system employs a flat panel detector with a 127 μm pixel pitch, and a micro focus x-ray tube with a focal spot size ranging from 5-30 μm. The system accommodates three magnification sets of 1.72, 2.54 and 5.10. The in-plane cutoff frequencies (10% MTF) ranged from 2.31 lp/mm (60 mm FOV, M=1.72, 2×2 binning) to 13 lp/mm (10 mm FOV, M=5.10, 1×1 binning). The results were qualitatively validated by a resolution bar pattern phantom and the smallest visible lines were in 30-40 μm range. Noise power spectrum (NPS) curves revealed that the noise peaks exponentially increased as the geometric magnification (M) increased. True in-plane pixel spacing and slice thickness were within 2% of the system's specifications. The CT numbers in cone beam modality are greatly affected by scattering and thus they do not remain the same in the three magnifications. A high linear relationship (R2 > 0.999) was found between the measured CT numbers and Hydroxyapatite (HA) loadings of the rods of a water filled mouse phantom. Projection images of a laser cut acrylic edge acquired at a small focal spot size of 5 μm with 1.5 fps revealed that noticeable phase effects occur at M=5.10 in the form of overshooting at the boundary of air and acrylic. In order to make the CT numbers consistent across all the scan settings, scatter correction methods may be a valuable improvement for this system.

Original languageEnglish (US)
Title of host publicationBiophotonics and Immune Responses XI
EditorsWei R. Chen
ISBN (Electronic)9781628419436
StatePublished - 2016
Externally publishedYes
EventBiophotonics and Immune Responses XI - San Francisco, United States
Duration: Feb 15 2016 → …

Publication series

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


ConferenceBiophotonics and Immune Responses XI
Country/TerritoryUnited States
CitySan Francisco
Period2/15/16 → …

ASJC Scopus subject areas

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


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