1. Institute of Radiation Physics Lausanne University Hospital Rue du Grand‐Pré 1 CH‐1007Lausanne Switzerland
2. Department of Nuclear and Corpuscular Physics University of Geneva Quai Ernest‐Ansermet 24 CH‐1211Geneva Switzerland
3. Department of Radiation Oncology Lausanne University Hospital Rue du Bugnon 46 CH‐1011Lausanne Switzerland