Incidental findings and safety events from magnetic resonance imaging simulation for head and neck radiation treatment planning: A single institution experience

•There is significant interest in replacing CT simulation with MR-only simulation for head and neck radiotherapy.•Since radiation oncologists are generally more familiar with CT than MRI, incidental findings from MRI sim may be more likely to be unrecognized without diagnostic radiology support.•Incidental findings were observed in similar proportions from CT or MRI sim (11%).•MRI sim detected non-oncologic important incidental findings in two patients that were not observed on the corresponding CT sim, both of which were identified by a neuroradiologist at the time of contour review.