Answer to Question #11792 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
I have some old lead aprons at my facility. When I x ray them for annual inspection, they have some wrinkles in the lead. You don't see this on the outside of the apron or shield—the outside integrity is fine—but you can feel it, and it shows on x-ray inspection. Do these wrinkled aprons need to be replaced? Also, what is a good x-ray technique for using computed radiography/direct radiography (CR/DR) to inspect the aprons/shields?
Wrinkles in the lead apron are acceptable as long as you don't see any corresponding lack of shielding in other areas (such as thin spots, tears, cracks, or pulling away from any edges). Think of a blanket that is spread on a bed—if there are wrinkles in the blanket, it is still effective for the area that it covers, but you want to be sure that it has not pulled away from any edges.
If you are using a radiographic x-ray unit to check lead aprons, you should find a technique setting that works well with your CR/DR system and that is not too dark or too light. A good place to start would be about 70 kilovolts potential (kVp) and 5 milliamp seconds (mAs), and you can adjust up or down from there as needed.
Kennith "Duke" Lovins, CHP