Target definition and treatment delivery
All patients must undergo pre-procedural cardiac imaging (chest/cardiac CT).Target volume delineation will be 4D-CT ITV based employing a 3–5 mm ITV to PTV margin. The ITV dose will be escalated from 27.0 Gy to an ITV prescription dose-equivalent level of maximum 35.1 Gy while keeping the PTV prescription dose constant at 25 Gy (Table Doses to OAR will be limited according to the recommendations published previously [
Summary of dose and fractionation schedules (all doses in Gy)