Answer to Question #9385 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment/Shielding — Shielding

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

What procedures/techniques are in place to shield patients in the operating room? There have been questions about more shielding to surgical patients, but most of the proposed solutions seem impractical. Gonadal shields used during lower vascular cases aren't feasible, orthopedics seems to have too little exposure time to warrant this protection, and with the beam originating from under the patient, accurately placing lead seems difficult. When placing the shield under the hips, not only are vital bony prominences not being padded, but during the case, the lead will transfer heat away from the patient, making it hard for anesthesia to retain temperature. There is no way to adjust the shield position after draping and the whole process, while beneficial in theory, seems troublesome to execute in practice. I appreciate your input.
You are entirely right that it is impractical to provide additional shielding to patients in an operating room (OR) environment. 

First you should understand that the Food and Drug Administration (FDA) regulations, specifically 21 CFR 1020.30 (k), already require that the x-ray tube housing be constructed to minimize x-ray leakage in all directions except through the collimator, which defines the x-ray field under examination. The air kerma rate at 1 meter from the tube housing shall not exceed 0.88 milligray/hour.  

In reality, x-ray tube housings can easily beat this performance standard and the addition of a lead apron to the patient's anatomy, outside of the area under examination, does not result in significant exposure reduction. However, in some cases, this practice may actually cause the patient to receive more exposure. If the lead apron is placed so that it encroaches into the x-ray field during the examination, it can cause the x-ray generator output to go up dramatically, resulting in increased radiation exposure to the area under examination.

So, I would not recommend employing lead aprons in this manner. They are there for occupational protection purposes. The exposure to the patient from one procedure, outside of the exam field, is very small. However, for OR personnel who are present chronically, it is recommended that they wear aprons to minimize their occupational exposure from multiple exams.

Mike Bohan
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