Dual-energy computed tomography (DECT) is a promising imaging modality. It has the potential to quantify different material densities and plays an important role in many clinical applications. To enable multiple material decomposition (MMD), the conventional analytical MMD algorithm assumes the presence of at most three materials in each image pixel, and each pixel is decomposed into a certain basis material triplet. However, the MMD algorithm requires strong prior knowledge of the mixture composition, and the decomposition performance is compromised around the boundaries of different compositions. In this work, we developed an analytical model based deep neural network MMD-Net to achieve multi-material decomposition in DECT. In particular, the type of the basis material triplet in each image pixel and the attenuation coefficients of each material are learned by dedicated convolution neural network modules, and the material-specific density maps are obtained from the analytical MMD algorithm. Physical experiments of a pig leg and a pork backbone specimen with inserted iodine concentrations were acquired to evaluate the performance of the MMD-Net. Results show that the proposed MMD-Net could provide high decomposition accuracy, and reduce the decomposition artifacts.
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