Metal artifacts are image distortions, typically appearing as dark bands or bright streaks, that occur in CT scans when high-density materials like metal are present in a sample. These artifacts generally result from phenomena such as photon starvation and beam hardening, obscuring details around metallic components in the reconstructed image.
To mitigate these effects, countermeasures can be implemented during the data acquisition phase or through software-based image reconstruction. Common techniques include:
- Increasing X-ray Tube Voltage: Raising the tube voltage enhances the penetration power of the X-rays, allowing them to pass through dense metals more effectively and reducing photon starvation.
- Using Beam Hardening Filters: Placing a metal filter (such as a thin copper plate) in the X-ray path absorbs low-energy X-rays before they reach the sample. This reduces beam hardening effects and improves image uniformity.
- Metal Artifact Reduction (MAR): Advanced reconstruction algorithms can also be used to mathematically correct and reduce streak artifacts in the final image.
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