I'm premed, so my views may be skewed...
I think they are definitely doctors, but they are in a different sense. Nowhere does it say you have to have the patient interaction these specialties don't. They are different (perhaps a little black sheepish), but they are VERY CRUCIAL to the wheel of medicine (about as close to the center as you can get).
Also, I know a doctor who is in interventional radiology, and even though he went to radiology school, he doesn't have the same job description as a "regular" radiologist. So don't let the title fool you
Mastashake