Haha -- while I was typing Sean 선생님 beat me to it! Have to start calling him Dr. Sean
Would you ever use 의사님 after the full name, e.g. 김수한 의사님 ? Is it ok to say 씨 at all for a person with a title like that?
I have heard the title 의사님, 박사님, and 선생님 used after a full name, mostly when there is a possibility of confusion about which person is being referred to. For example, if there are two Dr, Kim s at that particular hospital or university.
I'd say take Sean's advice on the 선생님 thing, he knows best. I personally wouldn't use 씨 or other honorific title (e.g. 선생님) to address someone with a doctorate degree unless they were being addressed with a title for a higher position, such as the director (원장) of the hospital/wing/ward etc. in that case you might address him/her with the title 원장님. Another example might be a person with a doctorate degree who is serving in an high government position, such as ambassador (대사) then we could say '대사님.' I figure they worked hard for that degree or position and I want to respect that even if I sound a bit awkward.
The Korean snack shop I frequent is inside a market in a building with a lot of other businesses, and there is a regular customer of the snack shop that is a doctor of Korean/Oriental medicine, we could address him as Dr.Lee, but everyone calls him 원장님 because he owns the building.
Oddly enough, dentists 치과 의사 are commonly called '선생님' --I guess it sucks to go to school for that long and get a degree in dentistry only to find out you are not a 'real' doctor --maybe it's the pain they inflict.. I dunno
A great Korean drama to recommend here would be 솔 약국 아들들 -- there's plenty of addressing doctors in that drama.