The frequency split method for helical cone-beam reconstruction

A new approximate method for the utilization of redundant data in helical cone-beam CT is presented. It is based on the observation that the original WEDGE method provides excellent image quality if only little more than 180° data are used for back-projection, and that significant low-frequency arti...

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Veröffentlicht in:Medical physics (Lancaster) 2004-08, Vol.31 (8), p.2230-2236
Hauptverfasser: Shechter, G., Köhler, Th, Altman, A., Proksa, R.
Format: Artikel
Sprache:eng
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Zusammenfassung:A new approximate method for the utilization of redundant data in helical cone-beam CT is presented. It is based on the observation that the original WEDGE method provides excellent image quality if only little more than 180° data are used for back-projection, and that significant low-frequency artifacts appear if a larger amount of redundant data are used. This degradation is compensated by the frequency split method: The low-frequency part of the image is reconstructed using little more than 180° of data, while the high frequency part is reconstructed using all data. The resulting algorithm shows no cone-beam artifacts in a simulation of a 64-row scanner. It is further shown that the frequency split method hardly degrades the signal-to-noise ratio of the reconstructed images and that it behaves robustly in the presence of motion.
ISSN:0094-2405
2473-4209
DOI:10.1118/1.1773622