Surgeon

A surgeon was a specialist in invasive medicine.

Harry Sullivan was a Royal Navy surgeon. (TV: Planet of the Spiders)

Cassandra O'Brien had two surgeons with her in later life who had a responsibility to moisturise her. Their absence led to the skin drying out and tearing violently. (TV: The End of the World)

Dr Grace Holloway, a cardiologist, performed surgery on the Seventh Doctor. (TV: Doctor Who)

To claim the Halassi Androvar from King Hydroflax, River Song hired a surgeon, sending Nardole to collect him. Nardole instead brought back the Twelfth Doctor, who had deemed "surgeon" a "close enough" title to his own, leaving the real surgeon behind. (TV: The Husbands of River Song)