Implementation of HybridArc treatment technique in preoperative radiotherapy of rectal cancer: dose patterns in target lesions and organs at risk as compared to helical Tomotherapy and RapidArc(2012)Auteurs: Thierry Gevaert, Benedikt Engels, Cristina Garibaldi, Dirk Verellen, Peter Deconinck, Michael Duchateau, Truus Reynders, Koen Tournel, Mark De Ridder