The influence of radiotherapy on the protein intake and muscle mass of patients has not been extensively investigated to date. It is also unclear whether the localization of the tumor disease and thus the radiation field have different effects. Therefore, with the pilot study presented here, we would like to record the nutritional uptake of patients before and after radiotherapy. The aim is to determine the amount of energy and protein intake as well as the timing of protein intake. Furthermore, the relationship between the timing of protein intake and muscle mass will be investigated.