中文摘要：

4D显微CT成像提供了活体动态成像信息，是一种新型、高效的疾病监测手段。为解决传统呼吸、心电门控技术和重建方法扫描时间长、成像剂量大以及图像运动伪影、信噪比低等缺陷，本文提出了一种将回顾性门控技术与先验图像约束的压缩感知重建算法（PriorImageConstrainedCompressedSensing，PICCS）相结合的4D显微CT扫描及重建方法。该方法利用了回顾性门控技术，通过显微CT的连续多圈扫描，提取小动物呼气阶段末相位的投影数据，并将其重建结果作为先验图像，再利用PICCS算法重建各心电相位下的数据，最终得到4DCT重建图像。小鼠成像实验结果表明，该4DCT重建方法能够得到无条状伪影的高质量重建结果，在均方误差（MSE）和峰值信噪比（PeakSignaltoNoiseRatio，PSNR）指标上均优于FDK和OSART算法。实现了快速扫描的同时，弥补了传统回顾性门控方法重建质量不足的缺陷，在扫描时间和重建质量上均优于其他方法。

英文摘要：

4D micro-CT imaging is a novelty and efficient method in disease surveillance and provides a living dynamic imaging information.Traditional cardio-respiratory gating strategies and micro-CT reconstruction methods have the disadvantages of long scanning time,high radiation dose,and motion artifact in reconstruction image.In order to solve those problems of traditional methods,this paper proposes a new4D CT scanning and reconstruction method based on the gating technique and the prior image constraint compressed sensing(PICCS)reconstruction algorithm.This method utilizes the retrospective gating technique which demands continuous scanning of multiple rotations,the reconstruction result of respiratory phase sorted projections is set as the prior image in the PICCS reconstruction.The experimental results demonstrate that the proposed method can effectively obtain4D reconstruction images with no streaking artifacts.4D micro-CT imaging using PICCS provides image quality superior to FDK and OSART algorithms in both MSE and Peak Signal to noise ratio(PSNR)calculations.This method can provide fast acquisition and better images over existing methods.