Answer to Question #4885 Submitted to "Ask the Experts"

Category: Radiation Workers — Pregnant Workers

The following question was answered by an expert in the appropriate field:

I work in a dental office as a dental assistant and I'm pregnant. I am concerned about radiation and I would like to know how much radiation each dental x ray carries and the amount of radiation that affects the baby. I try to stay far from the x-ray source but I'm concerned about scatter x rays; how far do I have to stay from the x-ray source? Also, do you think a lead apron with 0.3 mm thickness is sufficient to protect my baby from radiation?

Your concern about your radiation exposure during pregnancy is appropriate and appreciated. However, there is little cause for worry. Dental workers are very unlikely to receive much of a measurable occupational dose. There is an occupational dose limit (50 mSv per year—mSv is millisievert and is a unit of radiation dose) but I can share that at my organization, we have not had a dental assistant receive even 1/100^th of that (0.5 mSv) and we do many hundreds of dental x rays each year. Most of our dental workers, in fact, receive no measurable radiation exposure on the job.

There are a couple of reasons for this. First, the beam of radiation is coned to the exact spot that needs to be x rayed. So the only thing in the primary x-ray beam is the tooth or teeth of interest. Second, the fact that the beam is so coned down results in very little scatter radiation. In fact, because there is so little scatter radiation, the walls in a dental office generally do not need to have lead shielding in them.

The answer to your question about the 0.3 mm lead-equivalent apron is "yes." This amount of lead will stop 70-75 percent of the x rays in the primary beam and more of the scatter since those x rays have less energy.

Even if you were to be a patient and have some dental x rays done on you, there is no cause for concern for your baby. As well, the radiation exposure you receive in your occupation is too low, if there is any, to cause effects to your baby.

Kelly Classic
Certified Medical Health Physicist

Answer posted on October 17, 2005. The information and material posted on this Web site is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Web site. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.