In an adult, the radiation exposure from a typical abdominal CT examination is approximately equivalent to how many posteroanterior chest radiographs?

In an adult, the radiation exposure from a typical abdominal CT examination is approximately equivalent to how many posteroanterior chest radiographs?

• A. 50 chest radiographs
• B. 1000 chest radiographs
• C. 400 chest radiographs
• D. 2 chest radiographs

Answer: (C)

Abdominal CT delivers a dose on the order of several millisieverts (roughly about 8 mSv for a typical exam). A single chest radiograph (PA view) is about 0.02 mSv. Dividing 8 by 0.02 gives about 400, so the exposure from a typical abdominal CT is roughly equivalent to 400 PA chest radiographs. This magnitude helps put CT radiation in perspective: far more than a few chest X-rays, but not in the thousands. Variability exists with different scanners and protocols, but 400 chest X-rays is a commonly cited ballpark for comparison.

Abdominal CT delivers a dose on the order of several millisieverts (roughly about 8 mSv for a typical exam). A single chest radiograph (PA view) is about 0.02 mSv. Dividing 8 by 0.02 gives about 400, so the exposure from a typical abdominal CT is roughly equivalent to 400 PA chest radiographs. This magnitude helps put CT radiation in perspective: far more than a few chest X-rays, but not in the thousands. Variability exists with different scanners and protocols, but 400 chest X-rays is a commonly cited ballpark for comparison.