Which dose in millisieverts is associated with a 5.5% increase in the probability of developing cancer?

Which dose in millisieverts is associated with a 5.5% increase in the probability of developing cancer?

• A. 50 mSv
• B. 1000 mSv
• C. 150 mSv
• D. 500 mSv

Answer: (B)

The key idea is that cancer risk from radiation rises roughly in proportion to the dose for whole-body exposure in adults. A commonly used estimate is about 5% increased lifetime cancer risk per sievert (1 Sv). Since 1 Sv equals 1000 mSv, a dose of 1000 mSv is expected to produce about a 5% to 5.5% increase in cancer risk. The other options—the smaller doses—would correspond to much smaller increases (for example, 50 mSv is ~0.25%, 150 mSv ~0.75%, 500 mSv ~2.5%), which do not reach the 5.5% level. So the dose linked to about a 5.5% increase is 1000 mSv.

The key idea is that cancer risk from radiation rises roughly in proportion to the dose for whole-body exposure in adults. A commonly used estimate is about 5% increased lifetime cancer risk per sievert (1 Sv). Since 1 Sv equals 1000 mSv, a dose of 1000 mSv is expected to produce about a 5% to 5.5% increase in cancer risk. The other options—the smaller doses—would correspond to much smaller increases (for example, 50 mSv is ~0.25%, 150 mSv ~0.75%, 500 mSv ~2.5%), which do not reach the 5.5% level. So the dose linked to about a 5.5% increase is 1000 mSv.