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Protocol for the Evaluation of MRI Artifacts Caused by Metal Implants to Assess the Suitability of Implants and the Vulnerability of Pulse Sequences
Published on: May 17, 2018
A virtual sinogram method to reduce dental metallic implant artefacts in computed tomography-based attenuation
Mehrsima Abdoli1, Mohammad Reza Ay, Alireza Ahmadian
1Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Nuclear Medicine Communications
|October 16, 2009
Summary
This study introduces a new method to reduce metal artifacts in PET/CT scans caused by dental implants. The technique effectively corrects attenuation maps, improving image accuracy without complex data manipulation.
Area of Science:
- Medical Imaging
- Nuclear Medicine
- Radiological Physics
Background:
- Accurate attenuation maps (mumaps) are crucial for PET data correction.
- Metallic dental materials in CT scans cause streak artifacts, leading to inaccurate PET quantification.
- Existing metal artifact reduction (MAR) methods often struggle with proprietary raw CT data formats.
Purpose of the Study:
- To develop a practical approach for reducing metallic dental implant artifacts in PET attenuation maps.
- To improve the accuracy of PET data corrected using CT-based attenuation maps affected by dental work.
Main Methods:
- A novel MAR method using virtual sinograms generated from DICOM CT images.
- Segmentation of metallic objects in CT, forward projection of metal-only images to identify affected sinogram bins.
- Spline interpolation to replace artifact-affected sinogram data, validated with phantoms and patient data.
Main Results:
- The proposed MAR method significantly reduced visible metal artifacts in clinical settings.
- Mean relative error near metallic objects decreased by approximately 90%.
- No statistically significant differences were found between corrected and artifact-free PET images or corrected mumaps and theoretical values.
Conclusions:
- The developed MAR method offers a simple and convenient solution for correcting dental implant artifacts in PET/CT.
- The approach avoids manipulation of complex raw CT data.
- Further validation with a larger clinical PET/CT database is ongoing.
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