In patients with lung carcinoma who receive radiotherapy preoperatively or alternatively curative, high-dose radiotherapy instead of surgery, there are also deformations of the thorax from fraction to fraction. Currently, ART for lung carcinomas is carried out as part of patient care in the radiotherapy clinic. Patients are irradiated during repeated breath-holding manoeuvres in deep inspiration. The breath-holding manoeuvre is practised several times before the daily irradiation. An optical surface detection device is available for this purpose, which is used to compare the body surface in the patient's thorax area on the treatment table with the target surface to be achieved during radiotherapy planning, which took place days before the current fraction. If the target surface is reproducibly achieved, a conebeam CT is taken to determine the current tumour extent and the deformations occurring in comparison to the dose distribution to be applied. For this purpose, the normal tissues heart, lung and tracheal tree are automatically contoured by the Ethos therapy system in the cone-beam CT. A specialist physician and a physicist are present at the Ethos device during this process. These organ contours are used to determine the extent of the current target volume and the adaptive radiotherapy plan is adjusted to the new target volume. If the current tumour extent is not sufficiently covered by the initial radiotherapy plan planned for the series with its planned tolerances, or if the surrounding normal tissue is exposed to too much radiation, then the online adaptive radiotherapy plan for the current treatment is selected by the specialist. Otherwise, the initial radiotherapy plan is used by the planning CT as for IGRT. The aim of this study is to treat patients in ART readiness on the Ethos therapy device over 10 radiotherapy fractions. The dose distribution is always compared with the adaptive and the initial series plan on the anatomy of the day by the specialist and medical physics expert. The ART plan is applied when dosimetric advantages are present. The aim of this study is to prospectively analyse in how many patients safety margins around the clinical target volume can be reduced with ART compared to IGRT. The percentage of patients who benefit from ART will be determined prospectively. The criterion for a relevant benefit from ART is the effective uniform dose (EUD) in the target volume with the accumulated dose distribution across the first 7 fractions. If the EUD is below 95% of the target dose with IGRT and above 95% of the target dose with ART, then an advantage is determined with ART. Patients with a benefit from ART receive ART for the further fractions of the series, while the others continue to be treated with IGRT.