基于能谱匹配先验的多谱CT成像方法

现有的X射线CT成像系统，受限于多谱硬化伪影和传统单能假设的CT成像方法，只适用于结构分析却无法实现材料组分的有效区分。对此论文提出了基于能谱匹配先验的多谱CT成像方法。首先依据材料组分先验，构建能谱滤波匹配模型，设置能谱范围参数，并通过滤波获取该能谱范围内的多能投影序列;其次，针对多能投影序列，以材料组分为先验选择不同参考能量，采用改进后的ART迭代重建算法，实现了多谱CT成像。仿真实验结果表明，对于衰减系数相近的多种材质，通过选取两段不同能谱范围，重建出相应参考能量下的结果，在一定程度上改善了图像质量，对比度提高明显，可实现组分有效区分与成像。

Multi-Spectrum CT Imaging Method Based on Spectrum Matching Priors

In the process of X-ray computed tomography (CT) imaging,the traditional sing le-energy X-ray CT imaging technology is only applicableto structural analysis but can't meet the needs of functioning for su bstance distinction and identification because of the multispectral hardening ar tifacts and inconsistency between the projection acquisition process and reconst ruction assumption.A multispectral CT imaging method based on the spectrum mat ching priors is presented.First,energy spectrum filtering matching model is built andrange spectrum parameters are set according to the material composition;then multi-spectrum projection sequence is acquired by filtering.Second,the different reference energy is selected according to the material composition,befor using the improved Algebraic Reconstruction Techniques (ART) to achieve a multi-spectral CT imaging.Simulation result showsthat we improved the contrast of the reco nstructed image effectively,while meeting the needs of substance distinction.Th e actual data collection process is achieved by reconstructing in different spectrum and dif ferent corresponding reference energy.