In this study the radiotherapy is planned using 18F-FDG PET/CT making one experimental "dose-painting by contours" SIB (simultaneous integrated boost) plan with a maximum point dose of 75 Gy. The participants will be given 65 Gy and 70 Gy minimum doses to two GTVs inside the conventional GTV (60 Gy). GTV_65Gy and GTV_70Gy are determined from the SUV values from the 18F-FDG PET/CT according to the formula proposed by the Ghent group (Van der Straeten et al, R&O -06). It is expected to keep the level of normal tissue side-effects within or slightly above the level of conventional radiotherapy (i.e. maximum dose of 60 Gy). In addition to the routine follow-up, the participants will be examined with 18F-FDG PET/CT 6 months after inclusion (4 1/2 months after end of radiotherapy) and HRQL measurements.