Answer to Question #1903 Submitted to "Ask the Experts"

Q

I am a dental hygienist and work with x rays daily. I am 12 weeks pregnant and concerned about possible radiation exposure to my baby. This is a planned pregnancy and I felt confident that my baby was protected during x rays, although I recently read that the operator should stand at least six feet away from the source of radiation and wear an operator lead apron. I measured the distance and I am about five feet away from the source of radiation and stand outside the operatory behind a wall (which is not lead lined). In addition I also do not wear a lead apron. I have not told my employer about my pregnancy yet, but plan to do so soon and ask for a personnel monitor to ease my concerns. My question is, should I be concerned about possible exposure and also wear a lead apron?

A

Your concern about your radiation exposure during pregnancy is appropriate and appreciated. However, it is little cause for worry. In general, a standard partition consisting of two layers of drywall or Sheetrock is sufficient shielding for dental x rays. If the room layout permits, you should try to avoid having the primary beam pointed directly at you—even through the wall. You should obtain a personnel monitor (commonly called a "film badge") as soon as reasonably possible. It is extremely unlikely that any dental worker will receive an occupational dose greater than the current limit, 50 mSv per year. However, the limit for the embryo/fetus is 0.5 mSv per month during pregnancy. It is conceivable but not likely that you could exceed this limit. A monitor will provide inexpensive peace of mind. There is no evidence to suggest any harmful effect to you or your baby at doses below the above limit. It is also unlikely that a lead apron would be at all helpful to you. The personnel monitor would provide definitive information as to whether it is needed. You should not assume that 0.4 mSv per month is safe while 0.6 is harmful. The US National Council on Radiation Protection has concluded that there is no evidence of statistically significant increases in birth defects at doses below about 150 mSv during the term of pregnancy. So the occupational limit is set very conservatively.

S. Julian Gibbs, DDS, PhD