Limited Medical Radiologic Technologists (LMRT) Board Practice Exam

The primary barrier is specifically designed to provide protection from the primary beam of radiation generated during imaging procedures. This type of barrier typically includes walls or shields that are constructed from materials that effectively absorb radiation, allowing them to protect individuals in contiguous areas from exposure. The primary beam refers to the directed radiation emitted from the x-ray tube and is significantly stronger than scatter radiation.

In clinical settings, primary barriers must be positioned in areas where the central ray of the x-ray beam is expected to strike. For example, walls behind the imaging system where patients are positioned must have adequate thickness and density to absorb the primary beam, ensuring safety for personnel and patients outside the radiographic area.

The other types of barriers—like the aluminum barrier, protective barrier, and secondary barrier—serve different functions. Aluminum barriers generally provide filtration to absorb low-energy x-rays and are not intended to stop the primary beam. Protective barriers generally refer to shields that help reduce exposure from secondary radiation, such as scatter but do not encounter the primary beam directly. Secondary barriers are typically placed at a sufficient distance to protect against scattered radiation and leakage from the x-ray tube but do not interact with the primary beam during its production.

Thus, the primary barrier is crucial in ensuring safety in radiologic