1. Department of Radiation Therapy Liège, University Hospital Domaine Universitaire Sart Tilman, B34 4000 Liège1, Belgium
2. Academic Radiation Oncology Department Centre Oscar Lambret Service de Radiothérapie 3 rue Frédéric Combemale BP 307 59020 Lille Cedex - France
3. Gastrointestinal Oncology Department Centre Oscar Lambret Service de Radiothérapie 3 rue Frédéric Combemale BP 307 59020 Lille Cedex - France
4. Medical Imaging Department Centre Oscar Lambret Service de Radiothérapie 3 rue Frédéric Combemale BP 307 59020 Lille Cedex - France