Answer to Question #10265 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment/Shielding — Shielding

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

I am a veterinarian working in a hospital with a fixed GE HiSpeed computerized tomography (CT) scanner. Occasionally a person may need to be in the room with an anesthetized animal while the animal is undergoing a CT scan. If the person wears a lead apron and thyroid shield, will this be enough protection? Should we also purchase a mobile lead radiation barrier for the room? Is either safe enough?
Experience with human use of diagnostic x ray has shown that CT can deliver the highest radiation dose to persons in the x-ray room of any other diagnostic modality. Because of this, it is very important to not be in the room during the CT scan unless it is absolutely necessary. If an individual must be in the room during a scan, a mobile whole-body shield would provide the best protection if it is practical to use (for human use, it is common to have someone from respiratory therapy “bagging” a ventilator patient during a scan, whereby it is not possible to use a whole-body shield). If a whole-body shield is not practical, a lead apron with a minimum lead equivalence of 0.5 mm should be used along with a thyroid collar. The individual should be as far away from the center of the gantry as possible (i.e., increase distance from the x-ray source) and should always wear a radiation dosimeter. Radiation dose records for these individuals should be carefully monitored to make sure that the above practices are properly implemented and are effective.

Kennith “Duke” Lovins, CHP
Health Physicist
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