Within the framework of multimodal treatment (radiation, chemotherapy) of esophageal carcinoma high dose rate intracavitary irradiation is used either as a boost or with a palliative intention. By use of a set of four tubes of different thickness (diameter 6, 8, 10, 14 mm) it is possible to adapt the diameter of the applicator to the remaining esophageal lumen. Thereby the radioactive source is placed centrally in the esophagus. The distance between the source and the mucosa is maximized and the radiation dose to the mucosa is reduced in comparison to a normal tube with a diameter of 4 to 6 mm. Better depth penetration of the dose can be achieved in deeper parts of the esophageal wall. The applicators are placed using a guide wire during endoscopy. If the malignant stenosis is endoscopically impassable, an intraluminal reduction of the tumours mass is performed by laser therapy or bougienage.