16 March 2011 Single-scan scatter correction for cone-beam CT using a stationary beam blocker: a preliminary study
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Proceedings Volume 7961, Medical Imaging 2011: Physics of Medical Imaging; 796126 (2011); doi: 10.1117/12.878387
Event: SPIE Medical Imaging, 2011, Lake Buena Vista (Orlando), Florida, United States
Abstract
The performance of cone-beam CT (CBCT) is greatly limited by scatter artifacts. The existing measurement-based methods have promising advantages as a standard scatter correction solution, except that they currently require multiple scans or moving the beam blocker during data acquisition to compensate for the missing primary data. These approaches are therefore unpractical in clinical applications. In this work, we propose a new measurement-based scatter correction method to achieve accurate reconstruction with one single scan and a stationary beam blocker, two seemingly incompatible features which enable simple and effective scatter correction without increase of scan time or patient dose. Based on CT reconstruction theory, we distribute the blocked areas over one projection where primary signals are considered to be redundant in a full scan. The CT image quality is not degraded even with primary loss. Scatter is accurately estimated by interpolation and scatter-corrected CT images are obtained using an FDK-based reconstruction. In a Monte Carlo simulation study, we first optimize the beam blocker geometry using projections on the Shepp-Logan phantom and then carry out a complete simulation of a CBCT scan on a water phantom. With the scatter-to-primary ratio around 1.0, our method reduces the CT number error from 293 to 2.9 Hounsfield unit (HU) around the phantom center. The proposed approach is further evaluated on a CBCT tabletop system. On the Catphan©600 phantom, the reconstruction error is reduced from 202 to 10 HU in the selected region of interest after the proposed correction.
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Tianye Niu, Lei Zhu, "Single-scan scatter correction for cone-beam CT using a stationary beam blocker: a preliminary study", Proc. SPIE 7961, Medical Imaging 2011: Physics of Medical Imaging, 796126 (16 March 2011); doi: 10.1117/12.878387; https://doi.org/10.1117/12.878387
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KEYWORDS
Sensors

Scatter measurement

Reconstruction algorithms

X-ray computed tomography

X-rays

Computed tomography

Computer simulations

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