What percentage of the overall dose is contributed by CT?

• A. 10%
• B. 25%
• C. 35%
• D. 50%

Answer: (C)

The main idea here is understanding how the radiation dose from diagnostic imaging is distributed among different tests. CT scans deliver higher doses per examination than plain X-rays, and their use has grown a lot, so CT ends up contributing a large portion of the total dose accumulated from imaging procedures across the population.

In many dose-tracking sources, CT accounts for roughly one-third of the total diagnostic imaging dose to patients. That makes 35% the best fit among the options because it sits right around that commonly cited share. The exact figure can vary by country and year, but the mid-30s is a representative value for CT’s contribution.

The other options are less consistent with typical estimates: 10% would understate CT’s impact, 50% would imply CT alone dominates all imaging dose which isn’t the case, and 25% is plausible in some contexts but generally a bit low compared with the common teaching that CT is about one-third of the total.