In radiography, which barrier must be at least 1/16-inch lead equivalent?

• A. Lead apron
• B. Primary protective barrier
• C. Bucky slot cover
• D. Secondary protective barrier

Answer: (B)

The main point is shielding based on the path of the x-ray beam. The barrier that must be at least 1/16 inch lead equivalent is the primary protective barrier, the wall that directly intercepts the primary x-ray beam. It needs this thickness because it must attenuate the high-intensity primary radiation that could otherwise reach personnel in adjacent areas.

Lead aprons are personal protective gear for the wearer, not room barriers, so they’re not specified by this primary-beam standard. The Bucky slot cover is a shield around the device slot and protects against leakage through that slot, a secondary consideration rather than the primary beam interception. Secondary protective barriers are the walls not directly in the beam’s path and are designed to shield against scatter and leakage, which don’t require the same thickness as the primary barrier.