The noise navigator provides physiological motion detection completely independent of the imaging volume or contrast of the MR images and can be acquired on a much faster (millisecond) time scale than MRI. We believe that the noise navigator can be used as an independent verification method to detect the occurrence of motion in synergy with real-time MRI-guided radiotherapy and standalone during e.g. recontouring when typically no MRI is performed. For abdominothoracic radiotherapy, we investigated bulk motion and variable breathing as these have a relatively large amplitude (millimeters). Additionally, swallowing detection was investigated given its complications for head-and-neck radiotherapy.