What is the likelihood of a patient developing cancer in the short-term from a single radiologic exam?

• A. highly likely
• B. probable
• C. impossible
• D. highly unlikely

Answer: (D)

Radiation-induced cancer from a single diagnostic radiologic exam is a probabilistic, long-term risk, not a short-term one. Diagnostic X-ray doses are small, and the body can repair much of the damage; cancers from such exposure typically take many years to develop, often decades. So the immediate, short-term likelihood of developing cancer from one exam is extremely small, i.e., highly unlikely.

The other options would imply a meaningful short-term risk or no risk at all. There is some, though tiny, risk from any nonzero dose, so it isn’t truly impossible. But in the short term, the chance is so small that saying it’s highly unlikely is the best description.