In Apollo's role as a healer, his appellations included Acesius (ἈκÎσιος, Akesios, from ἄκεσις, "healing"), Acestor (ἈκÎστωÏ, AkestÅr, literally "healer"), Paean (Παιάν, PaiÄn, from παίειν, "to touch"), and Iatrus (ἸατÏός, IÄtros, literally "physician").
Iatros is just the Greek word for a doctor, a medical doctor. Apollo himself was inherently medicus.