Zhu Shouping, Tian Jie, Yan Guorui, Qin Chenghu, Feng Jinchao
Medical Image Processing Group, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China.
Int J Biomed Imaging. 2009;2009:960573. doi: 10.1155/2009/960573. Epub 2009 Sep 22.
A prototype cone-beam micro-CT system for small animal imaging has been developed by our group recently, which consists of a microfocus X-ray source, a three-dimensional programmable stage with object holder, and a flat-panel X-ray detector. It has a large field of view (FOV), which can acquire the whole body imaging of a normal-size mouse in a single scan which usually takes about several minutes or tens of minutes. FDK method is adopted for 3D reconstruction with Graphics Processing Unit (GPU) acceleration. In order to reconstruct images with high spatial resolution and low artifacts, raw data preprocessing and geometry calibration are implemented before reconstruction. A method which utilizes a wire phantom to estimate the residual horizontal offset of the detector is proposed, and 1D point spread function is used to assess the performance of geometric calibration quantitatively. System spatial resolution, image uniformity and noise, and low contrast resolution have been studied. Mouse images with and without contrast agent are illuminated in this paper. Experimental results show that the system is suitable for small animal imaging and is adequate to provide high-resolution anatomic information for bioluminescence tomography to build a dual modality system.
我们团队最近开发了一种用于小动物成像的锥形束微CT系统原型，它由一个微焦点X射线源、一个带有样品架的三维可编程平台和一个平板X射线探测器组成。它具有大视野（FOV），可以在一次扫描中获取正常大小小鼠的全身成像，通常需要几分钟或几十分钟。采用FDK方法进行三维重建，并通过图形处理单元（GPU）加速。为了重建具有高空间分辨率和低伪影的图像，在重建前进行原始数据预处理和几何校准。提出了一种利用线模体估计探测器残余水平偏移的方法，并使用一维点扩散函数定量评估几何校准的性能。研究了系统的空间分辨率、图像均匀性和噪声以及低对比度分辨率。本文展示了有和没有造影剂的小鼠图像。实验结果表明，该系统适用于小动物成像，足以提供高分辨率的解剖信息用于生物发光断层成像以构建双模态系统。
