Reduction of Beam-Hardening Artifacts in X-Ray CT

• Published in: 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference Vol. 2005; pp. 1865 - 1868
• Main Authors: Menvielle, N., Goussard, Y., Orban, D., Soulez, G.
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States IEEE 2005
• Subjects: Attenuation; Biological materials; Biological tissues; Computed tomography; Gradient methods; Image reconstruction; Implants; Reconstruction algorithms; Signal to noise ratio; X-ray imaging
• ISBN: 0780387414; 9780780387416
• ISSN: 1094-687X; 1557-170X; 1558-4615
• DOI: 10.1109/IEMBS.2005.1616814

Our goal is to decrease the importance of beam-hardening artifacts in X-ray computed tomography by addressing the polyenergetic nature of the X-ray source. We use the same physical model as De Man and al (1998). We next adopt an estimation framework for the reconstruction: the attenuation coefficients are determined by a likelihood-based estimator. This approach leads to minimization of an objective function which exhibits a complex structure. Nonetheless, we develop a numerical procedure with satisfactory numerical efficiency: we use a nonlinear conjugate gradient method. The three major contributions of this communication are: the positivity of the solution ensured by a change of variables, the convergence properties of the algorithm, and a satisfying computation time