Cone-beam (CB) acquisition is increasingly used for trulythree-dimensional X-ray computerized tomography (CT). However,tomographic reconstruction from data collected along a circulartrajectory with the popular Feldkamp algorithm is known to produce theso-called CB artifacts. These artifacts result from theincompleteness of the source trajectory and the resulting missingdata in the Radon space increasing with the distance to the planecontaining the source orbit. In the context of the development ofintegrated PET/CT microscanners, we introduced a noveloff-centered circular CT cone-beam geometry. We proposed ageneralized Feldkamp formula (α-FDK) adapted to thisgeometry, but reconstructions suffer from increased CB artifacts.In this paper, we evaluate and compare four differentreconstruction methods for correcting CB artifacts in off-centeredgeometry. We consider the α-FDK algorithm, theshift-variant FBP method derived from the T-FDK, an FBP methodbased on the Grangeat formula, and an iterative algebraic method(SART). The results show that the low contrast artifacts can beefficiently corrected by the shift-variant method and the SARTmethod to achieve good quality images at the expense of increasedcomputation time, but the geometrical deformations are still notcompensated for by these techniques.
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