Answer to Question #321 Submitted to "Ask the Experts"

Q

What are the effects and risks of working in a cardiac catheter lab. (x-ray radiation) and being pregnant?

A

Relative to other departments (radiology, GI, urology, operating rooms, etc.) that also use x-ray equipment, cardiac cath labs are generally considered high-dose areas. Because of the configuration of the x-ray equipment, the number of cases per day, and the often long period of fluoroscopy required for a study, personnel monitoring results for the staff members (who wear a single badge at the collar, outside of the lead apron) are generally the highest in the hospital. Literature has cited (and I have measured personally) exposure rates exceeding 500 mR/hr in cath labs. Please see other questions and answers in this "Ask the Expert" section related to radiation exposure and pregnancy for details regarding risk and effects. But please consider the following information with regard to minimizing exposure in cath labs.



Practice ALARA (keep your exposure as Low As Reasonably Achievable) considering TIME, DISTANCE, and SHIELDING. By minimizing your dose, the dose (and risk) to the fetus will be minimized. Minimize your time spent near the source of radiation exposure (the patient) or in the room. The cardiologists and technologists who stand right beside the patient receive the highest doses. But note that when the cardiologist exposes the patient he/she may actually "tap" on the foot control to minimize the exposure time. Maximize the distance between you and the source of exposure. Note that the highest exposure rates are located right about the part of the patient's body (the chest) being x rayed. That means you may reduce your exposure rate significantly by moving to the foot of the bed during procedures. Personnel often develop the habit of taking a couple of steps back away from the patient whenever the x-ray unit is turned on. Use whatever shielding is available. Always wear a lead apron in the room. Note that there are often lead drapes along the edge of the table to protect the cardiologist. Also, there are often portable shields in the room (even though the staff members are already wearing aprons). There may also be a ceiling-mounted shield for the cardiologist. Keep in mind that, while the doses to cath lab personnel are generally high, the dosimeters are worn at the collar outside of the lead apron—the dosimeters are measuring the "worst case" dose. The actual doses received by the employee's body are much, much lower because the lead aprons really work! (Some hospitals issue two badges to cath lab personnel—one to be worn at the collar outside of the apron and the other to be worn at the waist under the apron. The results of such monitoring are more realistic with regard to assigned doses.) I strongly encourage women to declare their pregnancy with the Radiation Safety Officer (RSO) as soon as possible. A dosimeter will be issued to employees to monitor fetal dose—it should be worn at the waist, under the lead apron. That way, the RSO and the mother can keep track of the fetal dose throughout the pregnancy. In my experience as an RSO, pregnant staff have had two major complaints:

1. The lead aprons are heavy, particularly the single-piece, "wrap around" aprons used in cath labs. That's why many cath lab staff members now use lead vests along with lead skirts—by distributing the weight better, the vest/apron combination causes less back strain (which may be a problem for a pregnant woman).
   
    


2. As the fetus grows, so does the woman's body. The available sizes of vests and skirts are often limited. So the pregnant women often use the single piece, nonwrap-around style used regularly in x-ray areas. If they use this style of apron, they just need to be aware of how they stand in the room (always keeping the protected side of the body towards the patient and x-ray equipment).

Again, although doses to cath lab personnel are generally high, they may be minimized by practicing ALARA. By minimizing the dose to the mother, the dose (and risk) to the fetus will also be minimized.



Carmine Plott, CHP, PhD