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10 March 2009 Cone-beam CT using a C-arm system as front end and a spherical spiral as source trajectory
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Proceedings Volume 7258, Medical Imaging 2009: Physics of Medical Imaging; 72580F (2009)
Event: SPIE Medical Imaging, 2009, Lake Buena Vista (Orlando Area), Florida, United States
C-arm systems may be used as front ends for cone-beam CT. The resulting image quality is affected by several factors, including the source trajectory, the reconstruction algorithm, and the accuracy of the data. The standard source trajectory is a circular arc spanning a little more than 180 degrees. However, since a planar source trajectory satisfies Tuy's completeness condition only within a subset of the source plane, the resulting images are bound to exhibit "cone-beam artifacts" off the source plane. The cure consists in using a source trajectory that satisfies Tuy's completeness condition everywhere within the volume of interest. Such a source trajectory must be non-planar. To keep the scan time short, the source trajectory should also consist of a single, smooth segment. A favorable source trajectory of this kind is a curve known as spherical spiral. We implemented a spherical spiral on a laboratory C-arm system, along with a standard circular arc. An anthropomorphic head phantom was scanned using both source trajectories and otherwise identical scan parameters. Images were reconstructed using a short scan version of the FDK algorithm (circular arc) and the cone-beam Fourierfiltered backprojection (CBFFBP) algorithm presented earlier. Images obtained with the circular arc showed cone-beam artifacts. Images obtained with the spherical spiral did not. The results also demonstrate the good performance of the CBFFBP algorithm.
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Hermann Schomberg, Peter van de Haar, and Wil Baaten "Cone-beam CT using a C-arm system as front end and a spherical spiral as source trajectory", Proc. SPIE 7258, Medical Imaging 2009: Physics of Medical Imaging, 72580F (10 March 2009);

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