Abstract

ARBOLEDA CLAVIJO, Carolina  and  PELC, Norbert J. IMAGE-QUALITY OPTIMIZATION FOR DUAL ENERGY COMPUTED TOMOGRAPHY (DECT) THREE-MATERIAL DECOMPOSITION. Rev. ing. biomed. [online]. 2009, vol.3, n.5, pp.33-42. ISSN 1909-9762.

Dual energy computed tomography, which consists of the acquisition of two images of a given region of interest using two different x-ray energies, has been used to decompose images. For example, it has been proposed to estimate the degree of stenosis of blood vessels with calcified plaques. Pragmatic realities, though, such as beam hardening, scattered radiation and mostly quantum noise, reduce the ideal of a perfect decomposition. In this study, a dual energy separation method for iodinated contrast media, cortical bone and soft tissue was implemented; afterwards, it was tested in simulated noiseless and noisy situations. The noise propagation was modeled mathematically, and an image-quality optimization technique regarding the right distribution of radiation dose between the high and low energy images was proposed. The results obtained suggest that in the absence of noise and using mono-energetic beams, an accurate separation is possible, but when noise is added and poly-chromatic spectra used this decomposition becomes more challenging.

Keywords : Dual energy computed tomography; Image-quality optimization technique; Linear attenuation coefficient; Material-decomposition algorithms; Noise propagation; Radiation dose.

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