1. Department of Computer Science, University of Applied Sciences and Arts, Dortmund, Germany
2. Institute of Medical Informatics, Biometry and Epidemiology, University Hospital Essen, Essen, Germany
3. Radiation and Tumor Clinic, University Hospital Essen, Essen, Germany
4. Surgical Clinic, University Hospital Essen, Essen, Germany
5. West German Cancer Center, University Hospital Essen, Essen, Germany