Answer to Question #11186 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment/Shielding — Shielding

The following question was answered by an expert in the appropriate field:

Q

This question builds upon the excellent information in Q8867 in your feature about scatter radiation while imaging neonates. In our 45-bed neonatal intensive care unit, we minimize the need for repeat imaging of mechanically ventilated babies by making sure the endotracheal tube is stabilized at the correct mark and the patient is midline. This may require the respiratory therapists to have their hands on the patient during an x-ray procedure. While staff members know to wear an apron and keep their hands out of the imaging field, their hands are still being exposed to some scatter. Assuming they do this two to three times a week for a 20- to 30-year career, should they be concerned?

A

The amount of scattered radiation the respiratory therapists' hands receive is dependent upon a number of factors. Given that these patients are neonates, the amount of radiation required to obtain adequate images is low. That in turn means the scattered radiation is low as well. Another factor is the location of the respiratory therapists' hands relative to the imaging field. Obviously, the closer to the imaging field, the higher the hand exposure. That said, I suspect the hand exposures are quite low.

Lead (Pb) gloves are available for purchase and could be worn by the respiratory therapists when their hands are near the imaging field; however, I would suggest that one or more of the respiratory therapists be provided with extremity radiation monitors (commonly referred to as "ring badges") for a period of time (about three months) to get an idea of how much hand exposure they actually receive. There should be someone at your facility designated as the radiation safety officer (RSO) who can obtain the ring badges and also help interpret the results. 

Another thing to consider is what your state regulations say regarding worker protection from occupational radiation exposure to extremities. State regulations vary from one state to another, so you may want to check and see if your state’s regulations require Pb gloves if the hands are in or near the imaging field. You should be able to obtain that information from either your RSO or your state regulatory agency.

As with the other state regulations, the occupational dose equivalent limits for extremities from x rays vary a bit among different states as well. The most commonly cited limit is 500 millisieverts (mSv) per year. Extremity monitoring is generally required by regulation if the extremity dose equivalent for an individual exceeds or is likely to exceed 10% of the limit (i.e., 50 mSv). If that is the case, I would recommend using Pb gloves which will reduce the hand exposure well below 10% of the occupational limit and eliminate the need to continue to provide ring badges. On the other hand, if the hand doses based upon the trial monitoring period described above are well below 10% of the occupational limit, neither ring badges nor Pb gloves would be necessary unless the state regulations specifically require them.

Mack L. Richard, MS, CHP

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 19 March 2015. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.