Christoph Pöttgen1, Ursula Nestle1, Stefan Höcht1, Martin Stuschke1. 1. Christoph Pöttgen, MD, PhD, Department of Radiation Oncology, West German Cancer Center, Medical Faculty, University Hospital Essen, Essen, Germany; Ursula Nestle, MD, PhD, Department of Radiation Oncology, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany, Department of Radiation Oncology, Kliniken Maria Hilf, Möchengladbach, Germany; Stefan Höcht, MD, PhD, Department of Radiotherapy, Xcare Group Practices, Saarlouis, Germany; and Martin Stuschke, MD, PhD, Department of Radiation Oncology, West German Cancer Center, Medical Faculty, University Hospital Essen, Essen, Germany.