利用X射线的连续能谱特性以及与物质作用后的丰富衰减信息，能谱CT(Spectral CT,SCT)有望弥补或解决常规CT所面临的高辐射剂量且仅为解剖成像的缺陷。然而，当前SCT成像中的辐射剂量较常规CT并未显著降低且在特定应用时反而大幅增加。囿于此，为使SCT更具临床生命力, 控制其辐射剂量已是CT领域亟待解决的关键性课题。本项目拟在保证诊断用影像质量的前提下，全力开展基于系统精准建模的超低剂量SCT优质成像新方法研究，其重点包括:(1)源于相关知识工程，构建精准的系统光学模型和系统统计模型，为超低剂量SCT投影数据校正与图像重建提供准确的测量方程；(2)结合SCT成像特点，构建基于系统模型的投影数据校正模型和图像重建模型，以期实现准确、鲁棒的超低剂量SCT优质成像；(3)基于校正的投影数据和重建图像，开展SCT参数成像及其分析与评价研究，以期获得准确的临床SCT影像诊断信息。

Using the energy spectrum of X-ray photons and the specific energy-dependent attenuation curve for each substance, spectral CT (SCT) is expected to overcome the drawbacks of conventional CT with high radiation dose but only performing anatomical imaging. However, current SCT imaging does not notably reduce the radiation dose and in some particular applications even greatly increase it as compared to the conventional CT imaging. In order to make the SCT more clinically appealing, controlling the radiation dose becomes a key problem to be solved. This project intends to carry out high-quality ultra low-dose SCT imaging with novel techniques based on accurate system modeling. The main contents include: (1) with the related knowledge, we construct an accurate imaging model and a statistical model to provide accurate measurement for ultra low-dose SCT projection data correction and image reconstruction; (2) based on the characteristics of SCT imaging and the system model, we construct projection data correction models and image reconstruction models to realize accurate and robust ultra low-dose SCT imaging; and (3) based on the corrected projection data and reconstructed images, we carry out SCT parameters imaging and perform the associated analysis and evaluations to yield accurate SCT diagnostic information.