what are the similiarities and differences between these 2 fields? I'm pretty sure you do a 5 yr diag radiology residency then a 1yr vascular/interventional fellowship and then you are an interventional radiologist. And a 5 yr rad onc residency and you are a radiation oncologist. Do rad oncs work exclusively on cancer? Do IRs to everything interventional that is not cancer? I know there's a lot of rads people out there, anyone wanna help me out with this one?