Scatter correction for cone-beam computed tomography using moving blocker

J. Wang, T. Solberg

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

Abstract

One well-recognized challenge of cone-beam computed tomography (CBCT) is the presence of scatter contamination within the projection images. Scatter degrades the CBCT image quality by decreasing the contrast, introducing shading artifacts and leading to inaccuracies in the reconstructed CT number. We propose a blocker-based approach to simultaneously estimate scatter signal and reconstruct the complete volume within the field of view (FOV) from a single CBCT scan. A physical strip attenuator (i.e., "blocker"), consists of lead strips, is inserted between the x-ray source and the patient. The blocker moves back and forth along z-axis during the gantry rotation. The two-dimensional (2D) scatter fluence is estimated by interpolating the signal from the blocked regions. A modified Feldkamp-Davis-Kress (FDK) algorithm and an iterative reconstruction based on the constraint optimization are used to reconstruct CBCT images from un-blocked projection data after the scatter signal is subtracted. An experimental study is performed to evaluate the performance of the proposed scatter correction scheme. The scatter-induced shading/ cupping artifacts are substantially reduced in CBCT using the proposed strategy. CT number errors in the selected regions of interest are reduced from 256 to less than 20. The proposed method allows us to simultaneously estimate the scatter signal in projection data, reduce the imaging dose and obtain complete volumetric information within the FOV.

Original languageEnglish (US)
Title of host publicationIFMBE Proceedings
Pages1824-1827
Number of pages4
Volume39 IFMBE
DOIs
Publication statusPublished - 2013
EventWorld Congress on Medical Physics and Biomedical Engineering - Beijing, China
Duration: May 26 2012May 31 2012

Other

OtherWorld Congress on Medical Physics and Biomedical Engineering
CountryChina
CityBeijing
Period5/26/125/31/12

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Keywords

  • computed tomography
  • cone-beam CT
  • imaging artifacts
  • moving blocker
  • Scatter correction

ASJC Scopus subject areas

  • Biomedical Engineering
  • Bioengineering

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