Karen Tracy, a medical technician in 2267
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.
Susan Khouri, Elizabeth's guardian, was a medical technician associated with Terra Prime in 2155. (ENT: "Demons")
Lieutenant Karen Tracy was one of the several medical technicians serving aboard the USS Enterprise prior to her death on Argelius II in 2267. (TOS: "Wolf in the Fold")
In the final draft of the script, she was specifically identified as a "psychotech".
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")
Ensign Maddy Calloway also served as a medical technician aboard the Enterprise-D in 2370. (TNG: "Eye of the Beholder")