Active raster scanning with carbon ions: reirradiation in patients with recurrent skull base chordomas and chondrosarcomas - Uhl, Matthias; Welzel, Thomas; Oelmann-Avendano, Jan Tobias; Habl, Gregor; Hauswald, Henrik; Jensen, Alexandra; Ellerbrock, Malte; Debus, Jürgen; Herfarth, Klaus (Strahlentherapie und Onkologie, 2014)