As a full performance DRT, perform a substantially full range of duties but receive guidance and directions regarding unfamiliar or unusual situations for more complex patient issues. These exams are performed without and with the use of contrast materials. The purpose of these exams is to achieve diagnostic studies in which proper diagnosis and treatment may be effectuated. United States Citizenship: Non-citizens may only be appointed when it is not possible to recruit qualified citizens in accordance with VA Policy. Certification. All applicants must be certified in general radiologic technology by the American Registry of Radiologic Technology, Radiography (ARRT) (R). Advanced ARRT certification is required for assignments that include computed tomography (CT), magnetic resonance imagin