Which artifact is characterized by a streak at the interface of high-density and lower-attenuation materials?

The artifact characterized by a streak at the interface of high-density and lower-attenuation materials is the edge gradient artifact. This type of artifact occurs due to the differences in X-ray attenuation between tissues of varying densities, leading to sharp gradients in the CT images at their interfaces. When high-density materials, such as bone, come into contact with softer tissues, the sharp change can result in streaks or bands around the edges, adversely affecting the image quality.

In the context of CT imaging physics, this phenomenon is important, as it can misrepresent anatomical structures and potentially mislead radiologists during interpretation. Understanding edge gradient artifacts can help technologists and radiologists recognize and account for these streaks when analyzing a scan, leading to more accurate diagnoses.

The other options refer to different types of artifacts that are generated by varying causes such as movement, changes in beam energy, or specific technical factors in the imaging process. However, they do not specifically relate to the streaking that occurs at the interface of high-density and lower-attenuation materials, making edge gradient artifact the appropriate choice in this scenario.