A 1.5 T magnetic resonance (MR)-equipped linear accelerator that enables online adaptive radiotherapy came on the scene in 2018. Here is an international prospective cohort of 1772 patients treated on a MR-linac between 2019-2021. This included all types of treatment from head to toe, the most common site being prostate (42%). Online adaptive radiotherapy was used in the majority of cases (59%). The primary outcome reported was acute toxicity within 3 months of treatment, which was exceedingly low across the entire cohort (1.4%) and also specifically across the cohort receiving online adaptive radiotherapy (0.4%). | Westerhoff, JAMA Netw Open 2024
