U.S. Air Force Staff Sgt. Matthew Stroud and Wayne Butler, 633rd Surgical Operations Squadron computed tomography technologists, perform a CT scan on a patient at Langley Air Force Base, Va., Nov. 14, 2014. CT scans are performed for diagnostic, treatment planning, interventional and screening purposes. (U.S. Air Force photo by Airman 1st Class Areca T. Wilson/Released)