2 March 2006 Motion artifacts from an inverse-geometry CT system with multiple detector arrays
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Abstract
Inverse-geometry CT (IGCT) is a promising new scanning geometry. Employing a scanned-anode x-ray source array the system is expected to provide sub-second volumetric imaging with isotropic resolution and no conebeam effects. Three detector arrays spaced apart laterally can achieve a 50 cm in-plane FOV with a 31 cm source. However, when three separate detector arrays are used, motion artifacts are expected to be different than in conventional CT and need to be assessed. Simulations were performed for two objects representing slow and fast motion as well as periodic and non-periodic motion. The simulations were repeated at different points in the FOV to study motion effects in three regions: 1) the inner 15 cm region which is sampled only by the central detector array, 2) the transition between the inner and outer regions, and 3) the outer region which is sampled by all three detector arrays. 2D simulations assumed 125 "superviews" acquired in step-and-shoot mode over 360 degrees. A gridding algorithm was used to resample the data into parallel rays which were then filtered and backprojected. Artifacts from the inner region are exactly like those that arise in a traditional CT system. The most significant artifacts caused by the multi-detector nature of the system are in the outer region, at the angles where the object sampling transitions between detector arrays. These streaking artifacts are comparable to motion artifacts in conventional CT and can be reduced by increasing the overlap region at the expense of FOV size and SNR uniformity.
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Samuel Mazin, Samuel Mazin, Norbert Pelc, Norbert Pelc, } "Motion artifacts from an inverse-geometry CT system with multiple detector arrays", Proc. SPIE 6142, Medical Imaging 2006: Physics of Medical Imaging, 61420G (2 March 2006); doi: 10.1117/12.653863; https://doi.org/10.1117/12.653863
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