Answer to Question #7133 Submitted to "Ask the Experts"

The radiation dose received by nursing personnel working in a nuclear stress laboratory is generally low and not a concern even if the individual is pregnant. However, it is always important to keep radiation dose ALARA (as low as reasonably achievable). In a nuclear stress laboratory this means appropriately applying the radiation safety principles of time, distance, shielding, and contamination control.

You specifically asked about applying shielding by wearing a lead apron. Although a lead apron significantly reduces radiation dose from low-energy photons emitted by an x-ray machine, a lead apron offers very little protection from the much more energetic photons emitted from either thallium (²⁰¹Tl) or sestamibi (^99mTc). A standard 0.5 mm lead apron reduces radiation from either ²⁰¹Tl or ^99mTc less than 1 percent, and a lead apron is not a recommended radiation safety device in a nuclear stress labortory.

In a nuclear stress laboratory, radiation doses to nursing personnel can favorably be reduced by applying the radiation safety principles of the time, distance, and contamination control. Minimize your time in any area where radiopharmaceutical dosages and/or patients who have recently been administered a radiopharmaceutical are present. Maximize distance whenever possible. Maximizing distance is one of the best and often easiest radiation safety principles to apply as a nurse in a nuclear stress laboratory. If you do not have to be in direct contact with a patient to perform your duties, step back a step or two. Moving from a couple of feet away to four feet away reduces your radiation exposure about a factor of four (400 percent). Perform good contamination control by practicing universal precautions, washing your hands, and monitoring yourself regularly.

Finally, although the radiation dose generally received by nursing personnel working in a nuclear stress laboratory is generally low and not a concern even if the individual is pregnant, confidence and piece of mind are also important. I recommend that you discuss your concerns and specific applications of radiation safety principles with your radiation safety officer. The radiation safety officer is responsible by regulation to ensure the radiation dose to you and your fetus are maintained within regulatory limits and are kept ALARA and to provide you guidance in regard to radiation safety. If desired, declare your pregnancy and request a fetal dosimeter. Although the doses detected by most dosimeters are not available for a period of time, they do document the dose received and frequently confirm the dose received is either indistinguishable from natural background or very low and that applying radiation safety principles minimized any radiation dose received.

Victoria Morris, MS, CHP