Which statement best describes beam hardening and streak artifacts on CBCT?

Which statement best describes beam hardening and streak artifacts on CBCT?

• A. They are caused by soft tissue only.
• B. They are reduced by metallic restorations.
• C. They appear as dark bands or streaks adjacent to metal restorations.
• D. They improve contrast resolution.

Answer: (C)

Beam hardening and streak artifacts on CBCT arise because the X-ray beam is polychromatic and dense materials, like metal restorations, change the spectrum of photons reaching the detector. As the beam passes through metal, many low-energy photons are absorbed more readily, raising the average energy of the transmitted beam. The reconstruction uses these altered projections, leading to inconsistent data and artifacts. A common manifestation is dark bands or streaks that appear adjacent to metal restorations; these streaks can also extend between dense objects due to photon starvation and data gaps. This degrades image quality and can obscure nearby anatomy. The statement that best describes this is that they appear as dark bands or streaks adjacent to metal restorations. They are not caused by soft tissue only, they are not reduced by metallic restorations, and they do not improve contrast resolution.

Beam hardening and streak artifacts on CBCT arise because the X-ray beam is polychromatic and dense materials, like metal restorations, change the spectrum of photons reaching the detector. As the beam passes through metal, many low-energy photons are absorbed more readily, raising the average energy of the transmitted beam. The reconstruction uses these altered projections, leading to inconsistent data and artifacts. A common manifestation is dark bands or streaks that appear adjacent to metal restorations; these streaks can also extend between dense objects due to photon starvation and data gaps. This degrades image quality and can obscure nearby anatomy. The statement that best describes this is that they appear as dark bands or streaks adjacent to metal restorations. They are not caused by soft tissue only, they are not reduced by metallic restorations, and they do not improve contrast resolution.