活体光学投影断层成像系统与应用

光学投影断层成像（Optical projection tomography，OPT）技术可以对1～10mm 尺度的低散射生物样本进行激发成像，具有微米级的空间分辨率、无辐射、成本低等特点，为小尺寸生物样本的高分辨率三维成像提供了一种新的手段. OPT最早通过对离体生物组织如小鼠胚胎、小鼠器官等成像，进行药物疗效评估、基因表达等研究，但是离体成像不能动态、完整地反映生物组织的变化，因此活体成像技术逐渐成为OPT领域的研究热点.本文详细介绍了我们自主研发的活体OPT系统，该成像系统以准直激光器为光源单元，高精密移动和旋转 电控平台为样本定位单元，低温电子倍增（Electron multiplying，EM） CCD探测器为采集单元，实现了针对果蝇蛹等小模式动物的活体三维成像.该系统的空间分辨率优于10 μm，成像视野1～10mm，扫描时间小于2min，重建时间小于5s.最后，本文通过果蝇蛹的三维活体成像实验展示该系统的操作流程、成像结果和初步的生物应用.

A Novel In-vivo Optical Projection Tomography System and Its Application

Optical projection tomography (OPT) is a low-cost and high-resolution imaging technology which can provide three-dimensional (3D) images for samples from 1 to 10mm. OPT has been greatly applied to drug efficacy evaluation or gene expression through imaging low SCAttering ex-vivo biological tissues, such as small animal extremities, animal embryos, etc. However, ex-vivo imaging cannot record dynamic change in biological tissues. Therefore, in-vivo application of OPT is promising. Our group has developed a novel OPT system for in-vivo imaging of small insects. The system consists of a continuous wave (CW) laser, three translation stages, a rotation stage, and a low-temperature electron multiplying (EM) CCD camera. The spatial resolution of our system is less than 10μm with an imaging field between 1mm and 10mm. An imaging experiment costs less than 2 min containing a 5s 3D reconstruction. Besides the system introduction, this paper also demonstrates the system operation processes and preliminary biological applications. Experimental results show that 3D in-vivo imaging of drosophila melanogaster pupae and other insects are easy to implement by using our system.