In a radiography suite, what barrier attenuates the primary useful beam?

• A. Primary Protective Barrier
• B. Secondary Protective Barrier
• C. Lead apron
• D. Door interlock

Answer: (A)

The barrier that attenuates the primary useful beam is the primary protective barrier. This wall is positioned in the path of the X-ray tube’s direct, forward-directed beam and is built with enough shielding to absorb most of that intense beam so that places beyond it receive only a safe level of exposure, even under heavy use. Lead aprons protect individuals from scattered radiation but don’t shield the primary beam at the room barrier. A door interlock is a safety feature to prevent exposure when the room isn’t properly secured, not a shielding barrier. The secondary protective barrier, by contrast, is designed to attenuate leakage and scattered radiation, not the primary beam.