TH-A-18C-07: Noise Suppression in Material Decomposition for Dual-Energy CT

Dong, X; Petrongolo, M; Wang, T; Zhu, L

doi:10.1118/1.4889566

Title: TH-A-18C-07: Noise Suppression in Material Decomposition for Dual-Energy CT

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Abstract

Purpose: A general problem of dual-energy CT (DECT) is that the decomposition is sensitive to noise in the two sets of dual-energy projection data, resulting in severely degraded qualities of decomposed images. We have previously proposed an iterative denoising method for DECT. Using a linear decomposition function, the method does not gain the full benefits of DECT on beam-hardening correction. In this work, we expand the framework of our iterative method to include non-linear decomposition models for noise suppression in DECT. Methods: We first obtain decomposed projections, which are free of beam-hardening artifacts, using a lookup table pre-measured on a calibration phantom. First-pass material images with high noise are reconstructed from the decomposed projections using standard filter-backprojection reconstruction. Noise on the decomposed images is then suppressed by an iterative method, which is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, we include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. Analytical formulae are derived to compute the variance-covariance matrix from the measured decomposition lookup table. Results: We have evaluated the proposed method via phantom studies. Usingmore »« less

Authors:

Dong, X; Petrongolo, M; Wang, T; Zhu, L ^[1]

Georgia Institute of Technology, Atlanta, GA (Georgia)

Publication Date:: Sun Jun 15 00:00:00 EDT 2014

OSTI Identifier:: 22409809

Resource Type:: Journal Article

Journal Name:: Medical Physics

Additional Journal Information:: Journal Volume: 41; Journal Issue: 6; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-2405

Country of Publication:: United States

Language:: English

Subject:: 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; COMPUTERIZED TOMOGRAPHY; DECOMPOSITION; ENERGY DEPENDENCE; ITERATIVE METHODS; NOISE; PHANTOMS; RADIATION QUALITY; SPATIAL RESOLUTION

Citation Formats


                    Dong, X, Petrongolo, M, Wang, T, and Zhu, L. TH-A-18C-07: Noise Suppression in Material Decomposition for Dual-Energy CT.  United States: N. p., 2014. 
        Web.  doi:10.1118/1.4889566.

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                    Dong, X, Petrongolo, M, Wang, T, & Zhu, L. TH-A-18C-07: Noise Suppression in Material Decomposition for Dual-Energy CT.  United States.  https://doi.org/10.1118/1.4889566

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                    Dong, X, Petrongolo, M, Wang, T, and Zhu, L. 2014.  
        "TH-A-18C-07: Noise Suppression in Material Decomposition for Dual-Energy CT".  United States.  https://doi.org/10.1118/1.4889566.

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@article{osti_22409809,

  title        = {TH-A-18C-07: Noise Suppression in Material Decomposition for Dual-Energy CT},

  author       = {Dong, X and Petrongolo, M and Wang, T and Zhu, L},

  abstractNote = {Purpose: A general problem of dual-energy CT (DECT) is that the decomposition is sensitive to noise in the two sets of dual-energy projection data, resulting in severely degraded qualities of decomposed images. We have previously proposed an iterative denoising method for DECT. Using a linear decomposition function, the method does not gain the full benefits of DECT on beam-hardening correction. In this work, we expand the framework of our iterative method to include non-linear decomposition models for noise suppression in DECT. Methods: We first obtain decomposed projections, which are free of beam-hardening artifacts, using a lookup table pre-measured on a calibration phantom. First-pass material images with high noise are reconstructed from the decomposed projections using standard filter-backprojection reconstruction. Noise on the decomposed images is then suppressed by an iterative method, which is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, we include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. Analytical formulae are derived to compute the variance-covariance matrix from the measured decomposition lookup table. Results: We have evaluated the proposed method via phantom studies. Using non-linear decomposition, our method effectively suppresses the streaking artifacts of beam-hardening and obtains more uniform images than our previous approach based on a linear model. The proposed method reduces the average noise standard deviation of two basis materials by one order of magnitude without sacrificing the spatial resolution. Conclusion: We propose a general framework of iterative denoising for material decomposition of DECT. Preliminary phantom studies have shown the proposed method improves the image uniformity and reduces noise level without resolution loss. In the future, we will perform more phantom studies to further validate the performance of the purposed method. This work is supported by a Varian MRA grant.},

  doi          = {10.1118/1.4889566},

  url          = {https://www.osti.gov/biblio/22409809},
  journal      = {Medical Physics},

  issn         = {0094-2405},

  number       = 6,

  volume       = 41,

  place        = {United States},

  year         = {Sun Jun 15 00:00:00 EDT 2014},

  month        = {Sun Jun 15 00:00:00 EDT 2014}

}

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