“…as surrogates of the lung tumor (Wang et al, 2007;Song et al, 2007;Bissonnette et al, 2009) while others perform image-guided lung radiotherapy by matching soft tissues (e.g., tumor, carina, etc.) directly (Guckenberger et al, 2007;Purdie et al, 2007;Grills et al, 2008;Yeung et al, 2009;Boda-Heggemann et al, 2011).…”