| Micro-CT system has played a critical role in the evolution of imaging technology. It can obtain high-spatial-resolution in-vivo or in-vitro anatomic information with relatively low cost and convenient operation, which has been used to the study of quantitative bone mineral density, vascular contrast, tumor monitoring, and can be combined with other modalities, such as nuclear imaging and optical imaging.Dramatic advances in imaging methods have been an important driving force in the development of molecular imaging. Each single imaging modality has its merits in one aspect. Multimodality fusion has been one important trend of imaging technology. SNR of the image can be improved with the advantages of different imaging modalities, which will provide more comprehensive and accurate detail information. Micro-CT system can be combined expediently with other modalities, such as nuclear imaging and optical imaging to achieve multimodality imaging.In this paper, a prototype cone-beam micro-CT system for small animal imaging has been developed. Reconstruction artifacts have been effectively reduced by 2D projection data preprocessing. In order to solve geometric offset of the micro-CT system, we propose a geometrical calibration method which utilizes system collimation and bearing-balls phantom. The system spatial resolution, image uniformity and noise levels, low contrast resolution, slice sensitivity and cone-beam artifact have been tested. A distinct intraperitoneal injection method using the common iohexol contrast agent (GE Healthcare) at 3 time points is presented to improve the contrast of the micro-CT volume data, which greatly increases the success rate of injection and reduce the cost. The different organs in the micro-CT volume data with high soft-tissue contrast are segmented by using dual- threshold, region growing and Live Wire segmentation methods. Finally, a micro-CT/BLT dual-modality experiment is designed to validate the BLT 3D reconstruction. |
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