Ah yes, I noticed her right away. Hopefully someone will have an answer on which med unit she might have been with at the time.
Good eye! 
I assumed she was a Nun or maybe some international Red Cross---definately a civilian. I think the US Red Cross wore uniforms. I've seen Red Cross uniforms that were nice and clean, like that one, but I doubt that was utilitarian for combat.
I should have asked my uncle who served in the Red Cross for years something during Korean War time or later.
Steve
Just added a 3rd Infantry Division pin to my collection today. Yeah!