中文摘要：

目的X射线计算机断层成像技术（computed tomography，CT）辐射剂量高于其它X射线检测。因为剂量累积效应会导致较高的致癌风险，因此降低剂量成为当前CT技术发展过程中亟待解决的问题。方法降低剂量的手段主要有降低管电流和增加探测器排数，但受相关因素制约，进一步降低剂量面临较大困难。本文提出一种基于X射线衰减水平的自适应非均匀采样方式，通过减少在高管电流区域的投影次数来降低剂量，并引入基于压缩传感的POCS—TVM算法从欠采样数据中恢复CT图像。结果实验结果表明该方法能在保证图像质量的同时有效降低剂量。结论基于压缩传感理论的CT剂量降低方法可以在保证重建图像满足临床诊断需求的前提下，有效降低辐射剂量，有利于受检者。

英文摘要：

Objective Because the dose of CT （computed tomography） is higher than other X-ray modalities and the accumulative effect of dose results in high carcinogenic risk, dose reduction is a big challenge in the development of CT technology. Methods Currently, methods including decrease of tube current and increase of detector rows have not been efficient enough for further close reduction. In this paper,we proposed a non-uniform self-adapting sampling method based on the X-ray attenuation. By decreasing the projection views in regions which have high tube current, the dose can be reduced. And POCS-TVM algorithm based on compressed sensing is applied to reconstructing CT image with insufficient sampling data. Results The results of experiments show that this approach can reduce the radioactive close significantly while ensure the acceptable quality of image. Conclusions The CT Dose reduction method based on a compressed sensing can reduce the dose and guarantee the clinical diagnostic quality of the reconstructed CT image,which benefits the subjects.