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Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT).

Publication ,  Journal Article
Ren, L; Yin, F-F; Chetty, IJ; Jaffray, DA; Jin, J-Y
Published in: Med Phys
August 2012

PURPOSE: To evaluate the feasibility of a synchronized moving grid (SMOG) system to remove scatter artifacts, improve the contrast-to-noise ratio (CNR), and reduce image lag artifacts in cone-beam CT (CBCT). METHODS: The SMOG system proposed here uses a rapidly oscillating, synchronized moving grid attached to the kV source. Multiple partial projections are taken at different grid positions to form a complete projection in each gantry position, before the gantry moves to the next position during a scan. The grid has a low transmission factor, and it is used for both scatter reduction and scatter measurement for postscan scatter correction. Experimental studies using a static grid and an enlarged CATphan phantom were performed to evaluate the potential CNR enhancement for different SMOG exposure numbers (1, 2, and 4). Simulation studies were performed to evaluate the image lag correction for different exposure numbers (2, 3, and 4) and grid interspace widths in SMOG using the data from an anthropomorphic pelvis phantom scan. Imaging dose of SMOG was also estimated by measuring the imaging dose in a CIRS CT dose phantom using a static grid. RESULTS: SMOG can enhance the CNR by 16% and 13% when increasing exposure number from 1 to 2 and from 2 to 4, respectively. This enhancement was more dramatic for larger phantoms and smaller initial exposure numbers. Simulation results indicated that SMOG could reduce the lag to less than 4.3% for 2-exposure mode and to less than 0.8% for 3-exposure mode when the grid interspace width was 1.4 cm. Increasing the number of exposures in SMOG dramatically reduced the residual lag in the image. Reducing the grid interspace width somewhat reduced the residual lag. Skin line artifacts were removed entirely in SMOG. Point dose measurement showed that imaging dose of SMOG at isocenter was similar as that of a conventional CBCT. CONCLUSIONS: Compared to our previously developed static-grid dual-rotation method, the proposed SMOG technique has the advantages of enhancing the CNR, correcting the image lag, and reducing the delivery time. Once implemented, SMOG has the potential to remove scatter and image lag artifacts, and significantly enhance CNR for CBCT using the same scanning time as conventional CBCT.

Duke Scholars

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

August 2012

Volume

39

Issue

8

Start / End Page

5099 / 5110

Location

United States

Related Subject Headings

  • Skin
  • Scattering, Radiation
  • Reproducibility of Results
  • Phantoms, Imaging
  • Oscillometry
  • Nuclear Medicine & Medical Imaging
  • Monte Carlo Method
  • Models, Statistical
  • Image Processing, Computer-Assisted
  • Humans
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Ren, L., Yin, F.-F., Chetty, I. J., Jaffray, D. A., & Jin, J.-Y. (2012). Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT). Med Phys, 39(8), 5099–5110. https://doi.org/10.1118/1.4736826
Ren, Lei, Fang-Fang Yin, Indrin J. Chetty, David A. Jaffray, and Jian-Yue Jin. “Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT).Med Phys 39, no. 8 (August 2012): 5099–5110. https://doi.org/10.1118/1.4736826.
Ren L, Yin F-F, Chetty IJ, Jaffray DA, Jin J-Y. Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT). Med Phys. 2012 Aug;39(8):5099–110.
Ren, Lei, et al. “Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT).Med Phys, vol. 39, no. 8, Aug. 2012, pp. 5099–110. Pubmed, doi:10.1118/1.4736826.
Ren L, Yin F-F, Chetty IJ, Jaffray DA, Jin J-Y. Feasibility study of a synchronized-moving-grid (SMOG) system to improve image quality in cone-beam computed tomography (CBCT). Med Phys. 2012 Aug;39(8):5099–5110.

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

August 2012

Volume

39

Issue

8

Start / End Page

5099 / 5110

Location

United States

Related Subject Headings

  • Skin
  • Scattering, Radiation
  • Reproducibility of Results
  • Phantoms, Imaging
  • Oscillometry
  • Nuclear Medicine & Medical Imaging
  • Monte Carlo Method
  • Models, Statistical
  • Image Processing, Computer-Assisted
  • Humans