A barrier used to attenuate stray radiation is termed?

• A. Secondary protective barrier
• B. Tertiary protective barrier
• C. Primary protective barrier
• D. Accessory barrier

Answer: (A)

Stray radiation refers to scatter and leakage from the x-ray tube, not the direct primary beam. The barrier that attenuates this type of radiation is the secondary protective barrier. It is specifically designed to absorb photons that escape the primary beam path or leak from the tube housing and to minimize exposure in areas adjacent to the examination room. This is distinct from the primary protective barrier, which is intended to stop the direct primary beam from reaching protected areas, and from a tertiary barrier, which is an extra shield used only in special circumstances when additional protection is needed. In practice, the secondary barrier = the shield that reduces exposure from scatter and leakage, keeping dose levels within allowed limits for nearby occupancies.