Yang Xiaoquan, Gong Hui, Quan Guotao, Deng Yong, Luo Qingming
Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Rev Sci Instrum. 2010 May;81(5):054304. doi: 10.1063/1.3422252.
We developed a dual-modality system that combines fluorescence diffuse optical tomography (fDOT) and flat panel detector-based microcomputed tomography (micro-CT) to simultaneously reveal molecular and structural information in small animals. In fDOT, a 748 nm diode laser was used as an excitation source, while a cooled charge coupled device camera was adopted to collect transmission fluorescence. In micro-CT, a flat panel detector based on amorphous silicon, with active area of 13 x 13 cm(2), and a microfocus x-ray tube were used. The fDOT system was mounted orthogonally to the micro-CT and the projection images were acquired without rotation of the sample, which is different from the method used for micro-CT alone. Both the finite element method and the algebraic reconstruction technique were used to reconstruct images from the fDOT. Phantom data showed that the resolution of the fDOT system was about 3 mm at an imaging depth of 7 mm. Quantitative error was no more than 5% and imaging sensitivity for 1,1(')-dioctadecyl-3,3,3('),3(')-etramethylindotricarbocyanine iodide bis-oleate (DiR-BOA) was estimated to be higher than 100 nM at a depth of 7 mm. Calculations of the phantom's center of mass showed that the location accuracy of fDOT was about 0.7 mm. We applied a Feldkamp algorithm to reconstruct the micro-CT image. By measuring the presampled modulation transfer function with a 30 microm tungsten thread, we estimated that the micro-CT has a resolution of 5 mm(-1) when the field of view was 6.5 cm. Our results indicate the uniformity of the transaxial micro-CT image and the contrast-to-noise ratio was measured as 1.95 for a radiation dose of 1 cGy. A non-image-based method was employed for merging images from the two imaging modalities. A nude mouse with DiR-BOA, imaged ex vivo, was used to validate the feasibility of the dual-modality system.
我们开发了一种双模态系统，该系统结合了荧光漫射光学断层扫描（fDOT）和平板探测器型微型计算机断层扫描（micro-CT），以同时揭示小动物体内的分子和结构信息。在fDOT中，使用748 nm二极管激光器作为激发源，同时采用冷却电荷耦合器件相机采集透射荧光。在micro-CT中，使用了基于非晶硅的平板探测器，其有效面积为13×13 cm²，以及一个微焦点X射线管。fDOT系统与micro-CT正交安装，且在不旋转样品的情况下采集投影图像，这与单独使用micro-CT的方法不同。有限元法和代数重建技术都被用于从fDOT重建图像。体模数据表明，fDOT系统在7 mm成像深度处的分辨率约为3 mm。定量误差不超过5%，在7 mm深度处，对1,1'-二辛基-3,3,3',3'-四甲基吲哚三碳菁碘化物双油酸酯（DiR-BOA）的成像灵敏度估计高于100 nM。体模质心计算表明，fDOT的定位精度约为0.7 mm。我们应用Feldkamp算法重建micro-CT图像。通过用30微米钨丝测量预采样调制传递函数，我们估计当视野为6.5 cm时，micro-CT的分辨率为5 mm⁻¹。我们的结果表明了横断面micro-CT图像的均匀性，在1 cGy辐射剂量下，对比度噪声比为1.95。采用一种基于非图像的方法来合并来自两种成像模态的图像。一只经DiR-BOA处理的裸鼠在离体状态下成像，用于验证双模态系统的可行性。
