1. Radiotherapy Department, Centre Eugene Marquis, Rennes, France;
2. INSERM U1099 LTSI, Rennes, France;
3. Université de Rennes 1, Rennes, France;
4. Radiotherapy Department, CHU Jean-Minjoz, Besançon, France;
5. Radiotherapy Department, Lausanne University Hospital, Lausanne, Switzerland