What is the minimum dose before there are in-utero effects to an unborn child?

• A. 5 Rem
• B. 10 Rem
• C. 15 Rem
• D. 20 Rem

Answer: (B)

The question tests the fetal dose threshold for deterministic effects. In radiation protection, there is a dose level below which observable in-utero effects are not expected, and above which the risk begins to rise. For X-ray and gamma exposures, this threshold is about 0.1 sievert, which equals 100 millisieverts or 10 rem. So the minimum dose at which in-utero effects could start to appear is around 10 rem. Doses lower than that (like 5 rem) are unlikely to cause deterministic fetal effects, while higher doses (15 or 20 rem) carry greater and more likely risk, depending on gestational age and exposure duration.