1. Center of Molecular Imaging, Radiotherapy and Oncology (MIRO), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium;
2. Department of Radiation Oncology, Cliniques universitaires Saint-Luc, Brussels, Belgium;
3. Department of Nuclear Medicine, Cliniques universitaires Saint-Luc, Brussels, Belgium;
4. Ion Beam Applications, Louvain-la-Neuve, Belgium;
5. Department of Epidemiology and Biostatistics (EPID), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium