Iran has produced a large amount of >60% U-235 (enriched), probably hundreds of kilograms, way more than would be required for any peaceful purpose. I don't think any modern medical uses actually require enriched uranium any more. And anyway, how much medical imaging or radiation treatment could you possibly be doing? And they could be developing propulsion systems, that wouldn't be a peaceful purpose (it would be a military ship).
Put all this together and it seems abundantly clear that the sole purpose of Iran's HEU program is the production of nuclear weapons. HEU isn't required in any significant amount for peaceful purposes.