Radiologist assistants, also called RAs, perform radiologic procedures and assess the health of patients using diagnostic imaging equipment. As an RA, you record patient medical histories, explain testing procedures to patients, and prepare the patient for testing. You work under the direct supervision of a qualified radiologist; you can screen the test result images, but you must have the radiologist review them for final approval. Radiologist assistants are mid-level positions in a radiology department; they have more skills and experience than radiologic technicians.