Hounsfield unit recovery in clinical cone beam CT images of the thorax acquired for image guided radiation therapy

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DOIResolve DOI: https://doi.org/10.1088/0031-9155/61/15/5781
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Name affiliation
  1. National Research Council Canada. Measurement Science and Standards
FormatText
TypeArticle
Journal titlePhysics in Medicine and Biology
ISSN0031-9155
1361-6560
Volume61
Pages5781–5802
Subjectcone beam CT; image guided radiotherapy; image quality; Monte Carlo
Abstract
A comprehensive artefact correction method for clinical cone beam CT (CBCT) images acquired for image guided radiation therapy (IGRT) on a commercial system is presented. The method is demonstrated to reduce artefacts and recover CT-like Hounsfield units (HU) in reconstructed CBCT images of five lung cancer patients. Projection image based artefact corrections of image lag, detector scatter, body scatter and beam hardening are described and applied to CBCT images of five lung cancer patients. Image quality is evaluated through visual appearance of the reconstructed images, HU-correspondence with the planning CT images, and total volume HU error. Artefacts are reduced and CT-like HUs are recovered in the artefact corrected CBCT images. Visual inspection confirms that artefacts are indeed suppressed by the proposed method, and the HU root mean square difference between reconstructed CBCTs and the reference CT images are reduced by 31% when using the artefact corrections compared to the standard clinical CBCT reconstruction. A versatile artefact correction method for clinical CBCT images acquired for IGRT has been developed. HU values are recovered in the corrected CBCT images. The proposed method relies on post processing of clinical projection images, and does not require patient specific optimisation. It is thus a powerful tool for image quality improvement of large numbers of CBCT images.
Publication date
PublisherIOP Publishing
LanguageEnglish
Peer reviewedYes
NPARC number23000512
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Record created2016-07-27
Record modified2020-03-16
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