A radiation therapy system including a radiation therapy apparatus for generating a therapeutic treatment beam, with which an object is irradiated, an imaging apparatus for generating a medical image of the object, and a positioning apparatus, with which the object is positioned in the radiation therapy system for irradiation and imaging purposes, is provided. The imaging apparatus and the radiation therapy apparatus are both rotatably mounted so that the object is positioned in a first rotation state in the imaging apparatus and is positioned in the radiation therapy apparatus in a second rotation state.