In the comic books, Banner's character is named Bruce Banner (from what I have read, "Robert Bruce Banner", though I'm not a diehard enough fan to know the origin of that) and he is a physicist.
I just started watching the 1978 show on Netflix, and the character's name is "David Banner", who is a physician/researcher.
Why was this change made? It doesn't seem like a trivial switch, and Stan Lee is credited as a consultant on the TV show, so it was not seemingly done to avoid any issues with copyrights.