Fetal dose is

• A. 0.03 mSv
• B. 0.3 mSv
• C. 3 mSv
• D. 0.003 mSv

Answer: (B)

Fetal dose is the amount of radiation absorbed by the fetus from dental imaging. Even though the doses are small, the fetus is more radiosensitive, so the aim is to keep any exposure as low as reasonably achievable (ALARA) and to use the minimum number of exposures necessary.

For a typical dental imaging session, the cumulative radiation reaching the fetus from a full set of radiographs is often in the tenths to few tenths of a millisievert range. The value around 0.3 mSv (which equals 0.0003 Sv) falls within a plausible estimate for a complete exam that might include several intraoral and panoramic exposures. The other options are either too small to represent a complete or common set of images, or too large to be expected from routine dental radiography.

Remember to apply shielding and minimize exposures whenever pregnancy is known or suspected, and to tailor the imaging plan to obtain the needed diagnostic information with the lowest reasonable dose.