moving (4D) targets, such as lung, liver or kidney is more complex mainly due to two factors: (1) interference between target and beam motion (interplay) and (2) the changing range to the target due to its [...] matter is a major advantage, but also require precise knowledge of the radiological pathlength to the target tissue. As this pathlength changes with motion especially in the lung, dedicated mitigation strategies [...] treatment planning software TRiP4D permits large-scale simulation studies both for cancer and non-cancer targets, for example the non-invasive treatment of cardiac arrhythmia. © GSI Helmholtzzentrum für Schwer