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PubMed · 17161556

Reducing metal artifacts in cone-beam CT images by preprocessing projection data.

Yongbin Zhang·Lifei Zhang·X Ronald Zhu·Andrew K Lee·Mark Chambers·Lei Dong
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Abstract

PURPOSE: Computed tomography (CT) streak artifacts caused by metallic implants remain a challenge for the automatic processing of image data. The impact of metal artifacts in the soft-tissue region is magnified in cone-beam CT (CBCT), because the soft-tissue contrast is usually lower in CBCT images. The goal of this study was to develop an effective offline processing technique to minimize the effect. METHODS AND MATERIALS: The geometry calibration cue of the CBCT system was used to track the position of the metal object in projection views. The three-dimensional (3D) representation of the object can be established from only two user-selected viewing angles. The position of the shadowed region in other views can be tracked by projecting the 3D coordinates of the object. Automatic image segmentation was used followed by a Laplacian diffusion method to replace the pixels inside the metal object with the boundary pixels. The modified projection data were then used to reconstruct a new CBCT image. The procedure was tested in phantoms, prostate cancer patients with implanted gold markers and metal prosthesis, and a head-and-neck patient with dental amalgam in the teeth. RESULTS: Both phantom and patient studies demonstrated that the procedure was able to minimize the metal artifacts. Soft-tissue visibility was improved near or away from the metal object. The processing time was 1-2 s per projection. CONCLUSION: We have implemented an effective metal artifact-suppressing algorithm to improve the quality of CBCT images.

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AlgorithmsArtifactsCalibrationDental AmalgamHead and Neck NeoplasmsHumansMaleMetalsPhantoms, ImagingProstatic NeoplasmsProstheses and ImplantsRadiographic Image EnhancementRadiotherapy Planning, Computer-AssistedTomography, X-Ray ComputedJournal Article

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Yongbin Zhang, Lifei Zhang, X Ronald Zhu, Andrew K Lee, Mark Chambers, Lei Dong. 2006-12-08. Reducing metal artifacts in cone-beam CT images by preprocessing projection data.. https://doi.org/10.1016/j.ijrobp.2006.09.045

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