“…Another way to mitigate motion-induced artifacts is to apply retrospective motion correction. To date several methods have been proposed for correcting for rigid motion (Wang and Vannier 1995, Schäfer et al 2004, Bodensteiner et al 2007, Yu and Wang 2007, Jacobson and Stayman 2008, Ens et al 2010, Zafar 2011, Bhowmik et al 2012 and nonrigid motion (Crawford et al 1996, Marchant et al 2001, Lu and Mackie 2002, Roux et al 2004, Schäfer et al 2004, Desbat et al 2007, Isola et al 2008, Taguchi and Kudo 2008, Rit et al 2009, Schretter et al 2009 in various types of CT imaging. In this paper we address the correction of rigid motion, characterized by six degrees-of-freedom (d.o.f.)…”