A medical technician was a technician skilled to perform various technical assignments in a medical field, usually in a medical facility such as sickbay. Such duties included operation of a psycho-tricorder and administration of medical injections to patients as needed.
During the 24th century, Starfleet Academy had a program for enlisted personnel with the option to train to become a medical technician. Crewman Simon Tarses served as a medical technician aboard the USS Enterprise-D in 2367. (TNG: "The Drumhead")