In case the TTD(Total Treatment Dose)=69Gy cannot be reached because of a limiting MLD, a FDG-PET-CT will be performed at day 12 during radiotherapy. GTV's (Gross Tmor Volume), CTV's (Clinical Target Volume) and PTV's (Planning Target Volume) will be delineated and a new plan calculated. The endpoint will be the proportion of patients that will receive 69Gy.