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