The invention relates to an antenna element (100) configured for positioning an anatomical structure of interest of a subject (218) in a position defined by the antenna element (100) for acquiring the magnetic resonance imaging data (244), to a positioning device (150) for positioning the anatomical structure of interest in the defined position on a support (348) of a medical radiation delivery system (300), to a fixating element (130) for fixating the anatomical structure of interest in the defined position on the antenna element (100) as well as on the positioning device (150).