Answer to Question #12793 Submitted to "Ask the Experts"

I'm a student and scrubbed in on a knee arthroscopy. I did not know x rays were being used until after I entered the procedure room and noticed the c-arm. I was not wearing a lead apron. My preceptor didn't have a lead apron on either, but the surgeons and anesthesiologist did. I made a comment about the need for a lead apron and was told I did not need one. The procedure only required a few images of the knee. I am now heading home and all that is going through my mind is that something bad is going to happen to me because I didn't wear a lead apron. Am I at risk for anything since I didn't? I'm 20 and there is no chance of me being pregnant now but in the future I really want children. Will this radiation affect my chance to have children in the future?

You are at no risk from your experience in the operating room with a c-arm. There is no chance of sterility or possible harm to future children you may have. The three main radiation protection principles in play here are summed up in three words: time, distance, and shielding.

Since you were not wearing radiation protection apparel such as a lead apron we will not consider shielding. (Some "lead" aprons don't have any lead in them, others are vests and skirts so they are not aprons; hence my use of the term "radiation protection apparel.") Although, if you were standing behind the surgeons, then you were shielded by both their radiation protection apparel and their body.  

Let's now consider distance. A good rule of thumb is that if you are not wearing radiation protective apparel, stand at least two meters (m) away from the part of the patient being x rayed and two m away from the x-ray tube (usually the part of the c-arm under the table). But since I don't know where you were during the x-ray imaging, I assumed you were right there next to the patient.  

In your case, therefore, the key factor is time. First, as you indicate, only a few images were taken, so the exposure time was short, perhaps several seconds of fluoroscopic on-time. For comparison, in cardiac catheterization procedures, the fluoroscopic on-time can be tens of minutes. During a difficult cardiac case, the fluoroscopy on-time can be over an hour! Also, you were there for only one procedure. If you were involved with procedures involving fluoroscopy five days a week, 50 weeks per year, the exposure time would be greater, and another means of protection (distance or shielding) would likely be in order.   

Another consideration is that the x-ray machine settings are based on the thickness of the body through which the x rays are going. Since the knee is thinner than, for example, the abdomen, the radiation output of the c-arm would be lower. 

Finally, consider this. The person getting by far the most radiation in the room is the patient. And their exposure is too low to put them in any risk.

The bottom line is that you are at absolutely no risk from your radiation exposure in the operating room. For more specific information, you should contact the hospital's radiation safety officer.  

Kent Lambert, CHP, FHPS