“…300-900) of uniformly distributed projection views, and analytic algorithms such as the FDK (Feldkamp et al 1984) or its variant are used for image reconstruction (Johnson et al 1998, Grass et al 1999, Wiesent et al 2000. There is also rapidly growing interest in developing optimization-based reconstruction for CBCT (Delaney and Bresler 1998, Elbakri and Fessler 2002, Sidky et al 2006, Pan et al 2009, Tang et al 2009, Stsepankou et al 2012, Nien and Fessler 2014, Wang et al 2014 especially in the context of OBI (Keall 2004, Yoo et al 2006, Bissonnette et al 2008, Wang et al 2008, Klein et al 2009, Choi et al 2010, Kim et al 2010, Tian et al 2011, Yan et al 2012, because it may possess some potential advantages over analytic reconstruction such as FDK in practical applications.…”