“…These methods align a 3D bone model, segmented from CT or MRI, with calibrated fluoroscopic sequences. Alignment is achieved by minimizing either an image intensity distance through calculation of digitally reconstructed radiographs (DRR) (Anderst et al, 2009; Bey et al, 2008; Dennis et al, 2005; Mahfouz et al, 2003; Muhit et al, 2010; Nakajima et al, 2007; Pickering et al, 2009; Scott and Barney Smith, 2006; You et al, 2001), or an image edge to bone model silhouette distance (Defrate et al, 2006; Fregly et al, 2005; Gollmer et al, 2007; Hanson et al, 2006; Hirokawa et al, 2008; Kitagawa et al, 2010; Li et al, 2008; Tersi et al, 2012; Torry et al, 2011; Tsai et al, 2010). Kinematic analysis not requiring the subject-specific 3D model would, however, be preferred, as it would lower analysis costs and eliminate the prior 3D acquisition resulting in lower radiation dose in the case of CT.…”