Duel Energy CT reconstruction

Dual-energy computed tomography (CT), which uses two X-ray spectra enabling material differentiation by analyzing material-dependent photo-electric and Compton effects, has become more widely used in various medical applications such as material decomposition and k-edge subtraction imaging. In most image reconstruction methods using Gaussian filtering, total variation (TV) for dual-energy CT, two CT images of high and low energies are separately reconstructed and utilized in applications. To improve the image quality by considering redundant information of both the high and low energy images, we propose a novel dual-energy CT reconstruction method using the guided image filtering algorithm, which jointly reconstructs two images of different energy spectra simultaneously. In our computer simulation, we demonstrate that the image quality can be significantly improved, which can be potentially exploited in material decomposition and radiation dose reduction. The proposed method will be validated using real experimental data of dual-energy CT.

(a) Ground truth and the reconstructed images of (b) FBP, (c) Gaussian filtering (FWHM=5mm), (d) SQS with TV and (e) the proposed method with (i) 80 kVp and (ii) 140 kVp, respectively. Here, color ranges are [0, 0.07] and [0, 0.035] for (i) and (ii).

H. Yang, K. Kim, G. El Fakhri, K. Kang, Y. Xing and Q. Li, Dual-energy CT Reconstruction using Guided Image Filtering, IEEE Nuclear Science Symposium and Medical Imaging Conference (NSSMIC), Nov. 2016.