Answer to Question #3771 Submitted to "Ask the Experts"

I am a resident in anesthesiology and am regularly involved in day-long surgical fluoroscopic procedures 3-10 days per month that may have cumulative fluoroscopy times of 150-200 minutes per day for one to four patients. We do wear protective aprons but are often unable to distance ourselves from the tube due to cramped rooms and our equipment. Additionally, we have not been provided with any monitoring badges despite repeated requests. Does our potential exposure warrant monitoring and would a leaded portable screen be preferable to a leaded apron?

It is unusual for surgical procedures to require more than 10 minutes of fluoroscopy time, and most require much less than 10 minutes. If your numbers are correct, that is, 150 to 200 minutes of fluoroscopy time for one to four patients, or 38 to 200 minutes per patient, then you have some potentially serious problems that need to be addressed. Fluoroscopy times of 200 minutes on a single patient have the potential for radiation doses that can exceed the skin response level for the patient. Such long fluoroscopy times could certainly lead to doses to staff in excess of the occupational limits.

The best approach would be to address your concerns to the Chief of Radiology and the Radiation Safety Officer (RSO). If fluoroscopy times typically exceed 10 minutes, this might indicate a need for additional training for the operators of the x-ray units or assistance from radiologists or radiology residents for difficult-to-image patients. It might also indicate a need for testing of the fluoroscopy equipment to assure that it is operating properly and providing quality images for reasonable doses. The RSO should be able to provide or arrange for testing of the equipment, an evaluation of the potential doses to patients, and typical scatter radiation to staff who are in the room during the procedures. The RSO can also determine if personnel monitoring or some other method of monitoring is indicated for evaluation of staff exposures.

What you describe is not consistent with our experiences. Our monitoring indicates:

1. Fluoroscopy times used during surgery are usually less than 10 minutes per case.
    
2. Typical doses for our anesthesiologists are less than 1 mSv (100 mrem) per year for measurements made with the film badge worn on the outside of the leaded apron.
    
3. Leaded aprons absorb greater than 90% of the diagnostic x rays scattered to them with the conventional (0.5 mm lead equivalent) aprons absorbing greater than 99% of the scattered x rays.

Leaded aprons do not protect the thyroid gland or lens of the eyes from scattered radiation. Leaded thyroid collars and leaded glasses must also be worn when there is potential for high doses from scattered x rays. Leaded mobile screens are available that can shield the entire body from scattered radiation.

Kenneth L. Miller, CHP, CMHP
Penn State Hershey Medical Center