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Proceedings Paper

An experimental study on the noise correlation properties of CBCT projection data
Author(s): Hua Zhang; Luo Ouyang; Jianhua Ma; Jing Huang; Wufan Chen; Jing Wang
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Paper Abstract

In this study, we systematically investigated the noise correlation properties among detector bins of CBCT projection data by analyzing repeated projection measurements. The measurements were performed on a TrueBeam on-board CBCT imaging system with a 4030CB flat panel detector. An anthropomorphic male pelvis phantom was used to acquire 500 repeated projection data at six different dose levels from 0.1 mAs to 1.6 mAs per projection at three fixed angles. To minimize the influence of the lag effect, lag correction was performed on the consecutively acquired projection data. The noise correlation coefficient between detector bin pairs was calculated from the corrected projection data. The noise correlation among CBCT projection data was then incorporated into the covariance matrix of the penalized weighted least-squares (PWLS) criterion for noise reduction of low-dose CBCT. The analyses of the repeated measurements show that noise correlation coefficients are non-zero between the nearest neighboring bins of CBCT projection data. The average noise correlation coefficients for the first- and second- order neighbors are 0.20 and 0.06, respectively. The noise correlation coefficients are independent of the dose level. Reconstruction of the pelvis phantom shows that the PWLS criterion with consideration of noise correlation results in a lower noise level as compared to the PWLS criterion without considering the noise correlation at the matched resolution.

Paper Details

Date Published: 19 March 2014
PDF: 9 pages
Proc. SPIE 9033, Medical Imaging 2014: Physics of Medical Imaging, 90332R (19 March 2014); doi: 10.1117/12.2043151
Show Author Affiliations
Hua Zhang, Southern Medical Univ. (China)
The Univ. of Texas Southwestern Medical Ctr. at Dallas (United States)
Luo Ouyang, The Univ. of Texas Southwestern Medical Ctr. at Dallas (United States)
Jianhua Ma, Southern Medical Univ. (China)
Jing Huang, Southern Medical Univ. (China)
Wufan Chen, Southern Medical Univ. (China)
Jing Wang, The Univ. of Texas Southwestern Medical Ctr. at Dallas (United States)

Published in SPIE Proceedings Vol. 9033:
Medical Imaging 2014: Physics of Medical Imaging
Bruce R. Whiting; Christoph Hoeschen, Editor(s)

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