Which of the following is NOT an example of structural barrier used for shielding?

A radiation apron is designed to be worn by individuals as personal protective equipment and is not considered a structural barrier. Structural barriers are fixed installations that provide protection from radiation by absorbing or scattering it.

Examples of structural barriers include materials like lead, concrete, or steel that are built into the environment, such as a wall, door, or window. These barriers are designed to reduce radiation exposure for individuals in adjacent areas or rooms.

In contrast, a radiation apron is intended to be used by individuals and can be moved or removed easily. While it serves to protect the wearer from radiation exposure, it does not function as an inherent part of the building structure meant to shield radiation in a specific area.