Final answer:
The series of radiographic images taken after oral administration of barium is called an upper GI series. This procedure is used to visualize and diagnose conditions in the upper gastrointestinal tract such as ulcers and acid reflux disease by making those regions visible on an X-ray.
Step-by-step explanation:
The series of radiographic images described in the student's question are known as an upper GI series. An upper GI series is a medical procedure that involves the oral administration of a contrast agent, usually barium, to delineate the structures of the pharynx, esophagus, stomach, and duodenum for diagnostic imaging. Barium is an excellent contrast medium because its high atomic mass renders it opaque to X-rays, making it possible to visualize the anatomy and assess for any abnormalities such as ulcers, acid reflux disease, or Crohn's disease.
Other procedures mentioned, such as an endoscopic ultrasound or endoscopic retrograde cholangiopancreatography (ERCP), involve the use of an endoscope to assess other aspects of the gastrointestinal tract or biliary system. A barium enema is a different procedure involving the introduction of barium sulfate into the colon for imaging.