Protection of Organs at Risk

Adaptive radiotherapy (ART) includes image-guided radiotherapy (IGRT) and also offers further possibilities for plan adaptation. A particularly high benefit can be expected for patients in whom the clinical target volume (CTV) can show a significant change in shape from fraction to fraction due to anatomical deviations. The shape and position constancy of the CTV during the course of the series is examined in this trial. Dosimetric disadvantages of this type have not been reported so far. The aim of this study is to identify patients who benefit from ART at an early stage and to select them for this method, and then to continue to offer ART to this patient group. If a relevant reduction in the minimum planning target volume (PTV) margins with ART compared to IGRT is demonstrated in this study, patients could be treated with ART.