What I referred to as ""earlier versions of Elekta" is "not an earlier version of the Elekta Unity." For example, Elekta HD, mistakenly indicated by AI as no longer in use. There are several of these non-MR Linac machines at Sunnybrook, and they didn't retire them all when Sunny installed the first MR-Linac in Canada. The Wing of the building I was treated on, there's a huge sign MR-Guided Radiotherapy. I came to understand that it meant MRI-Guided treatment for a few patients needing more real-time accuracy (e.g., patients who cannot ha e fiducial markers) and MRI-Guided simulation/planning for most patients who get a mini-CT scan before each SBRT treatment (comparing the mini-CT images with the planning images, and the care team making adjustments before each treatment). At least, this is my understanding -- and this is probably be more accurate than AI's statement that Elekta HDs are no longer used at Sunnybrook.