1. Department of Radiation Oncology, CyberKnife and Radiation Therapy, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
2. Zentrum für Radiotherapie, Rüti, Switzerland
3. Radiotherapy and Radiosurgery Department, Humanitas Research Hospital and Cancer Center, Milan-Rozzano, Italy
4. German Hodgkin Study Group, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
5. Department of Biomedical Sciences, Humanitas University, Milan-Rozzano, Italy
6. Department of Hematology and Oncology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany