Answer to Question #4704 Submitted to "Ask the Experts"

Q

Can you give me information regarding the safety of a radiologist doing fluoroscopy while pregnant? Is a double apron necessary? We stand much closer to the tower than technologists.

A

I'm going to make a couple of assumptions for my reply. One is that you wear radiation dosimeters (badges) and the other is that you wear a 0.5 mm lead-equivalent apron during the procedures.

From the radiation dosimeter you wear on your collar outside the lead apron, you can determine the approximate exposure under the apron by dividing by 21 ( National Council on Radiation Protection and Measurements Report 122). That gives a very conservative estimate of your abdominal dose. For instance, if your collar badge reads 250 mrem a month, then you could estimate your abdominal dose to be about 12 mrem.

In reality, a 0.5 mm lead-equivalent apron stops nearly all of the secondary x rays coming from the patient and about 97% of primary-beam x rays. Relative to your question about wearing a second lead apron, it probably would only add to your back pain. Two aprons might stop 98-99% of the beam—not much better than one apron.

The dose limit to the fetus of an occupational worker during the gestation period is 500 mrem. Where I work, we have an average of 20 to 25 pregnant radiation workers at any given time. No one has ever come close to or exceeded the dose limit. For those who wear a lead apron, the doses are always zero for the badge worn under the apron.

So, no need for a second apron. I realize you need to be closer to the patient but one thing you might try is to take one or two extra steps away from the location where the beam enters the patient—move toward the patient's head or feet but still stay close. An extra foot or two away can reduce your dose by up to a factor of 10.

Kelly Classic
Certified Medical Health Physicist