Which artifact is commonly seen with metallic objects and has a tail-like appearance?

Which artifact is commonly seen with metallic objects and has a tail-like appearance?

• A. Ring-down
• B. Comet tail artifact
• C. Refraction
• D. Mirror image

Answer: (B)

The main idea is that dense metal in an image tends to produce streaks that radiate away from the object, creating a tail-like appearance. This is the comet tail artifact. It happens because the metal heavily attenuates the X-ray beam, causing beam hardening and scattered photons to align into bright linear streaks that extend from the object. You’ll often see this with dental fillings or surgical hardware; the tail-like lines can obscure nearby structures, but the pattern is distinctive enough to identify the artifact as comet tail. Other terms describe different phenomena (ring-like patterns from other modalities, refraction effects, or image duplication), which don’t produce the characteristic tail extending from a metallic object.

The main idea is that dense metal in an image tends to produce streaks that radiate away from the object, creating a tail-like appearance. This is the comet tail artifact. It happens because the metal heavily attenuates the X-ray beam, causing beam hardening and scattered photons to align into bright linear streaks that extend from the object. You’ll often see this with dental fillings or surgical hardware; the tail-like lines can obscure nearby structures, but the pattern is distinctive enough to identify the artifact as comet tail. Other terms describe different phenomena (ring-like patterns from other modalities, refraction effects, or image duplication), which don’t produce the characteristic tail extending from a metallic object.