American Registry of Radiologic Technologists (ARRT) Practice Exam

The term that refers to a grid artifact occurring when using stationary grids is known as the Moire effect. This artifact typically arises from the interaction between the linear grid lines and the digital imaging system’s pixel array, leading to visible lines or patterns on the final image.

In radiography, stationary grids are used to improve image contrast by reducing scatter radiation. However, when the grid lines are aligned or closely spaced in relation to the pixel structure of the imaging detector, interference patterns can emerge, resulting in the distinct appearance that characterizes the Moire effect. Recognizing this effect is important for radiologic technologists, as it can obscure diagnostic information and must be addressed to ensure high-quality imaging.

The other terms relate to different concepts in imaging and do not describe the specific problem associated with stationary grids. Aliasing artifacts are generally associated with sampling issues in digital imaging, pseudomasking pertains to certain visualization techniques or imaging methods, and beam hardening relates to the alteration of x-ray beam quality due to the absorption characteristics of the tissue. Understanding the specifics of these terms can help further clarify why the Moire effect is the most appropriate answer in this context.

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