An iterative maximum-likelihood polychromatic algorithm for CT

• Published in: IEEE transactions on medical imaging Vol. 20; no. 10; pp. 999 - 1008
• Main Authors: De Man, B., Nuyts, J., Dupont, P., Marchal, G., Suetens, P.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.10.2001; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Attenuation; Biological and medical sciences; Computed tomography; Extraterrestrial measurements; Hospitals; Image Processing, Computer-Assisted - methods; Image reconstruction; Investigative techniques, diagnostic techniques (general aspects); Iterative algorithms; Medical sciences; Miscellaneous. Technology; Models, Theoretical; Nuclear medicine; Phantoms, Imaging; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Reconstruction algorithms; Tomography, X-Ray Computed - instrumentation; Tomography, X-Ray Computed - methods; X-ray imaging; X-ray scattering; Human; Radiodiagnosis; Image processing; Iterative method; Acquisition; Algorithm; Scattering factor; Image reconstruction; Simulation; Attenuation coefficient; Medical imagery; Computerized axial tomography; Maximum likelihood; Computing method; Test object
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/42.959297

A new iterative maximum-likelihood reconstruction algorithm for X-ray computed tomography is presented. The algorithm prevents beam hardening artifacts by incorporating a polychromatic acquisition model. The continuous spectrum of the X-ray tube is modeled as a number of discrete energies. The energy dependence of the attenuation is taken into account by decomposing the linear attenuation coefficient into a photoelectric component and a Compton scatter component. The relative weight of these components is constrained based on prior material assumptions. Excellent results are obtained for simulations and for phantom measurements. Beam-hardening artifacts are effectively eliminated. The relation with existing algorithms is discussed. The results confirm that improving the acquisition model assumed by the reconstruction algorithm results in reduced artifacts. Preliminary results indicate that metal artifact reduction is a very promising application for this new algorithm.