Li Changqing, Mitchell Gregory S, Dutta Joyita, Ahn Sangtae, Leahy Richard M, Cherry Simon R
Department of Biomedical Engineering, UC Davis, Davis, CA 95616, USA.
Opt Express. 2009 Apr 27;17(9):7571-85. doi: 10.1364/oe.17.007571.
We have developed a three dimensional (3D) multispectral fluorescence optical tomography small animal imaging system with an innovative geometry using a truncated conical mirror, allowing simultaneous viewing of the entire surface of the animal by an EMCCD camera. A conical mirror collects photons approximately three times more efficiently than a flat mirror. An x-y mirror scanning system makes it possible to scan a collimated excitation laser beam to any location on the mouse surface. A pattern of structured light incident on the small animal surface is used to extract the surface geometry for reconstruction. A finite element based algorithm is applied to model photon propagation in the turbid media and a preconditioned conjugate gradient (PCG) method is used to solve the large linear system matrix. The reconstruction algorithm and the system feasibility are evaluated by phantom experiments. These experiments show that multispectral measurements improve the spatial resolution of reconstructed images. Finally, an in vivo imaging study of a xenograft tumor in a mouse shows good correlation of the reconstructed image with the location of the fluorescence probe as determined by subsequent optical imaging of cryosections of the mouse.
我们开发了一种三维（3D）多光谱荧光光学断层扫描小动物成像系统，该系统采用创新的几何结构，使用截头圆锥镜，可通过电子倍增电荷耦合器件（EMCCD）相机同时观察动物的整个表面。圆锥镜收集光子的效率比平面镜高约三倍。一个x-y镜扫描系统使准直的激发激光束能够扫描到小鼠表面的任何位置。入射在小动物表面的结构光图案用于提取表面几何形状以进行重建。应用基于有限元的算法对光子在混浊介质中的传播进行建模，并使用预处理共轭梯度（PCG）方法求解大型线性系统矩阵。通过体模实验评估重建算法和系统的可行性。这些实验表明，多光谱测量提高了重建图像的空间分辨率。最后，对小鼠体内异种移植肿瘤的活体成像研究表明，重建图像与通过小鼠冷冻切片的后续光学成像确定的荧光探针位置具有良好的相关性。
