Noise reduction in low-dose cone beam CT by incorporating prior volumetric image information

L. Ouyang, T. Solberg, J. Wang

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


Repeated use of cone beam CT (CBCT) in radiotherapy introduces extra imaging dose to patients. In this work, we propose a method to effectively reduce the imaging dose of on-treatment CBCT by incorporating previously acquired CBCT. The Karhunen-Loève (KL) transform was used to consider the correlation among the on-treatment low dose CBCT and prior CBCTs in the projection domain. Following the KL transform, the selected CBCT projection data were decomposed into un-correlated, ordered principle components. Then, a penalized weighted least-squares (PWLS) criterion was applied to restore each KL component using different penalty strengths, where the penalty parameter was inversely proportional to its corresponding KL eigenvalue. Following the inverse KL transform on the processed data, the FDK algorithm was used to reconstruct the on-treatment CBCT image. The proposed algorithm was evaluated using both a CatPhan 600 phantom and an anthropomorphic head phantom. The proposed algorithm demonstrated the ability to suppress noise while preserving edge information effectively. This new strategy outperforms the PWLS algorithm without considering prior information based on the noise-resolution tradeoff measurement and analyze of the reconstructed small objects. Information extracted from previously acquired CBCT can be effectively utilized to suppress noise in on-treatment low-dose CBCT. The presented strategy can significantly lower the patient CBCT radiation dose without compromising the quality of the images.

Original languageEnglish (US)
Title of host publicationWorld Congress on Medical Physics and Biomedical Engineering
Number of pages4
StatePublished - 2013
EventWorld Congress on Medical Physics and Biomedical Engineering - Beijing, China
Duration: May 26 2012May 31 2012

Publication series

NameIFMBE Proceedings
Volume39 IFMBE
ISSN (Print)1680-0737


OtherWorld Congress on Medical Physics and Biomedical Engineering


  • KL transform
  • Low-dose cone beam CT
  • PWLS
  • principal component analysis
  • prior information

ASJC Scopus subject areas

  • Bioengineering
  • Biomedical Engineering


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