Answer to Question #1149 Submitted to "Ask the Experts"

Q

I am an operating-room nurse. I am pregnant and am concerned about the exposure to x rays, as we do many. I am shielded, but is that enough? Also, does it matter how many weeks pregnant I am?

A

Well, first, congratulations are in order! Being pregnant in the workplace certainly increases our awareness of what hazards might exist. In your case, it sounds like you're exposed to some of the x rays that might be taken during surgical cases. You didn't say whether you wore a radiation badge or not. I'll assume not so we'll make some assumptions about the amount of exposure you might be receiving. Before we go any further, though, we're going to use 500 mrem as our comparison number as this is the typical radiation exposure limit for the fetus of a pregnant radiation worker. Your lead apron is one of the best defenses against radiation exposure. It will stop about 95% of the x rays. The tissue in your abdomen also offers some protection for the fetus. Another method of protection that can significantly reduce your exposure is to move farther away from the point where the x-ray beam is interacting with the patient. This doesn't mean you have to move away from the table (but do so if you can), you can move up or down the length of the table and still increase your distance without getting too far from the patient. There is a general rule of thumb that says if you're about a foot away from where the beam enters the patient, you receive about 1% of the dose the patient receives; if you're three feet away, it decreases to about 0.1%. Decreasing time is another way to reduce exposure but I'm guessing you might not have much control over that. Let's use an example. If a standard abdominal film is being taken (patient exposure is about 250 mR; a pelvis film is similar but extremity x rays are much less), and you're standing one foot away and wearing a lead apron (one-foot distance reduces your dose by 99% and the lead apron reduces that by another 95%), your body under the apron would receive less than one mrem. Use the apron and distance to your advantage. By doing so, you'll keep the baby's and your exposure well below any limits.

Kelly Classic
Certified Medical Health Physicist