Have radiologists routinely cheated for years on medical exams to get board-certified by getting the actual answers in advance? That’s what a doctor at renowned military hospital alleges has been going on for at least a decade. He provided CNN with several years of what’s known as “recalls” – the actual questions and answers from real exams.

Here’s how it works – right after the test is completed, the test taker immediately writes down the questions and answers. These are compiled and shared with other residents who will be taking the test.

CNN's Drew Griffin investigates the use of “recall exams” by radiology residents – a practice the American Board of Radiology calls cheating.

One of three riveting stories airing on CNN Presents Saturday at 8:00 pm ET, reairing at 11:00 pm ET and 2:00 am ET.