Training is a lot longer than that in Québec, radiology is a specialty, so they must first do their 5 years in medicine, followed by a 5 year diagnostic radiology residency program. And it's frequently followed by a 2 years fellowship.

So 5 + 5 + [0,2] is [10,12] years of training.

Residents are working doctors, so we’d start losing useful work the year we stop taking new residents.

'people should stop training radiologists now'

That sentence and what you wrote are not 100% the same.