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Metal Artifact Reduction in Cone Beam Computed Tomography

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Title Metal Artifact Reduction in Cone Beam Computed Tomography
Speaker Manuel Meilinger
Institution Universität Regensburg
Date 2009/07/06
Time 15:00
Location Anfiteatro V
Country Portugal

Abstract

In cone-beam computed tomography (CBCT) images, much like in computed tomography (CT) images, high density objects, especially metal parts, generate streak-like artifacts. We present a novel method for metal artifact reduction in CBCT images via virtual replacement of the metal objects in the 3D volume with objects of identical geometry but water like x-ray attenuation coefficient. The algorithm described in this article is designed for mobile C-arm systems. As the 3D scan procedure for CBCT of mobile C-arm systems is not completely reproducible in its projection geometry and computed forward projections are elementary for this method an additional correction based on mutual information, using an edge filter as preprocessing step, must account for these misalignments. A reconstruction of the adapted 2D projection images generates a second 3D volume, where the originally metal objects now have a density like water and the streak-like artifacts are clearly reduced. Last step is to transfer the segmented metal parts of the first 3D volume into the metal and artifact free 3D volume of the second reconstruction. The proposed method is applied to clinical images and shows superior performance. The resulting reconstructed images show much reduced streak-like artifacts and related shadows.

About the speaker

Manuel Meilinger is with the Computational Intelligence and Machine Learning Group, Prof. Dr. E. W. Lang, Institut für Biophysik und physikalische Biochemie, Universität Regensburg.