1. Department of Radiation Oncology and Cyberknife Center, University Hospital of Cologne, Cologne, Germany;
2. German Hodgkin Study Group, University Hospital of Cologne, Cologne, Germany;
3. Radiation Oncology, Bonn-Rhein-Sieg, Siegbur, Germany;
4. Department of Radiooncology, Marienhospital, Düsseldorf, Germany;
5. Department of Radiology, University Hospital of Cologne, Cologne, Germany;
6. Department of Nuclear Medicine, University Hospital of Cologne, Cologne, Germany;
7. Department of Radiation Oncology, University Hospital of Muenster, Munster, Germany;
8. Department of Internal Medicine and Hematology, University Hospital of Cologne, Cologne, Germany