Quantitative Reconstruction of Dual K-Edge Contrast Agent Distribution for Photon- Counting Computed Tomography

Contrast-enhanced Computed Tomography (CT) imaging is very helpful for the detection of tumor metastasis and cancer cells. It is one of the most effective means of clinical imaging examination. The objective of this paper is to realize the quantitative reconstruction of two contrast agents at the same time and obtain the non-contrast-enhanced images in four energy bins as an additional product. This paper presents an iterative material decomposition method based on volume conservation and K-edge characteristics. Compared with other K-edge based material decomposition algorithms, the proposed method can simultaneously quantify the two contrast agents and make better use of the energy information provided by the photon-counting detector. The proposed algorithm was compared with the image-domain K-edge subtraction, Angular Rejection and filtered back projection (FBP) reconstruction. Numerical simulation and Monte Carlo simulation were used to verify the effectiveness of the proposed algorithm. We found that the proposed algorithm has higher efficiency and is meaningful for the quantification of contrast agent concentration. The proposed algorithm can achieve the quantitative separation of dual K-edge contrast agent by a single scan, which is significant for reducing the radiation dose to patients and improving the efficiency of material decomposition.