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Computed Tomography using projection X-ray microscope for Biological materials

使用投影 X 射线显微镜进行生物材料计算机断层扫描

基本信息

批准号：
10680643
负责人：
YOSHIMURA Hideyuki
金额：
$ 2.11万
依托单位：
Meiji University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

The projection X-ray microscope makes use of a very small X-ray source from a thin (0.1-3 μm) target metal film that is excited by the focused electron beam of a scanning electron microscope (SEM). If an object is placed just below the target metal film, the diverging X-rays enlarge the shadow of the object. Because the size of X-ray light source is less than 100nm, the resolution of this microscope is about 0.1μm which is better than that of optical microscopes. We have applied this microscope for three-dimensional (3-D) structure analysis by means of cone-beam computerized tomography. The projection images of small insect, Omiscus Porcellio, were recorded in every 1° for whole direction (360°) with a stepping motor controlled sample rotator. An Omiscus Porcellio was prepared by critical point drying method and fixed on a thin adhesive tape (0.4μm thick) of the sample rotator. The images were recorded with cooled CCD camera (HAMAMATSU C4880) which detect X-ray directly. The 3-D image was reconstructed from corn-beam projections using back-projection algorithm. The resolution of the reconstructed 3-D image (256 x 256 x 256) was about 3 μm. The digestive organs were clearly visualized in 3-D.We are going to analyze smaller objects such as nerve networks which contains more detailed structure.

投影X射线显微镜利用来自薄（0.1-3 μm）靶金属膜的非常小的X射线源，该靶金属膜由扫描电子显微镜（SEM）的聚焦电子束激发。如果一个物体被放置在目标金属膜的正下方，发散的X射线会放大物体的阴影。由于X射线光源的尺寸小于100 nm，该显微镜的分辨率约为0.1μm，优于光学显微镜。我们已经应用这种显微镜的三维（3-D）结构分析通过锥形束计算机断层扫描。利用步进电机控制的样品旋转器，在全方位（360°）上每隔1°记录小昆虫Omiscus Porcellio的投影图像。用临界点干燥法制备了一种稀米粥，并将其固定在样品旋转器的薄胶带（0.4μm厚）上。用直接探测X射线的冷CCD摄像机（HAMAMATSU C4880）记录图像。利用反投影算法从玉米束投影重建三维图像。重建的三维图像（256 × 256 × 256）的分辨率约为3 μm。消化器官在3D中清晰可见。我们将分析更小的对象，如神经网络，它包含更详细的结构。