You could probably do it in urgent care too
You could do it in Primary Care if you had a hospitalist system at your hospital, but you would still have to take call (but home call answering questions about runny noses and things through your answering service, but if you worked in an area and had a large group you could make this minimal, I know docs who do it 1-2 times per month).
Radiology can do it, especially if you use overseas reading companies for night and weekend call, you would only really be called if you were an interventionalist or the overseas system was down
What about pathology? I have no idea, but call cannot be that busy
What about PM&R?
The last two are just theories, I have seen the first three.