Use of sphere phantoms to measure the 3D MTF of FDK reconstructions

Jongduk Baek, Norbert J. Pelc

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

10 Citations (Scopus)

Abstract

To assess the resolution performance of modern CT scanners, a method to measure the 3D MTF is needed. Computationally, a point object is an ideal test phantom but is difficult to apply experimentally. Recently, Thornton et al. described a method to measure the directional MTF using a sphere phantom. We tested this method for FDK reconstructions by simulating a sphere and a point object centered at (0.01 cm, 0.01 cm, 0.01 cm) and (0.01 cm, 0.01 cm, 10.01 cm) and compared the directional MTF estimated from the reconstructed sphere with that measured from an ideal point object. While the estimated MTF from the sphere centered at (0.01 cm, 0.01 cm, 0.01 cm) showed excellent agreement with that from the point object, the estimated MTF from a sphere centered at (0.01 cm, 0.01 cm, 10.01 cm) had significant errors, especially along the fz axis. We found that this is caused by the long tails of the impulse response of the FDK reconstruction far off the central plane. We developed and tested a new method to estimate the directional MTF using the sphere data. The new method showed excellent agreement with the MTF from an ideal point object. Caution should be used when applying the original method in cases where the impulse response may be wide.

Original languageEnglish
Title of host publicationMedical Imaging 2011
Subtitle of host publicationPhysics of Medical Imaging
PublisherSPIE
ISBN (Print)9780819485038
DOIs
Publication statusPublished - 2011 Jan 1

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7961
ISSN (Print)1605-7422

All Science Journal Classification (ASJC) codes

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

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  • Cite this

    Baek, J., & Pelc, N. J. (2011). Use of sphere phantoms to measure the 3D MTF of FDK reconstructions. In Medical Imaging 2011: Physics of Medical Imaging [79610D] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 7961). SPIE. https://doi.org/10.1117/12.878850