“…CBCT projections) With implanted markers: Cho et al, 2010 Without implanted markers: Martin et al, 2012 Two views, fixed With implanted markers: Schweikard et al, 2000;Schweikard et al, 2004a;Berbeco et al, 2005;Ionascu et al, 2007;Seppenwoolde et al, 2007;Cho et al, 2008;Ruan et al, 2008;Hoogeman et al, 2009;Cho et al, 2010;Torshabi et al, 2010;Cho et al, 2011 Without implanted markers: Schweikard et al, 2004b;Shechter et al, 2004;Schweikard et al, 2005;Shechter et al, 2005;Shechter et al, 2006;Schneider et al, 2010PET/SPECT Klein et al, 2001Ambwani et al, 2011US Atkinson et al, 2001Ernst et al, 2011Miscellaneous Electromagnetic tracking Timinger et al, 2004 From 4-D XCAT phantom Rahni et al, 2011 and type of surrogate signals used, as well as the choice of correspondence model. For indirect correspondence models (see Section 5.3.2) the internal variables that parameterise the model determine what type of motion and variation can be modelled.…”