Development and its medical/biological application of a projection X-ray microscope using synchrotron radiation.

发展了以同步辐射为光源的软X射线投影显微术。该系统由最外波带宽度为80 nm的菲涅耳波带片、针孔（0.5-20μmφ）、样品保持器和背照式CCD相机组成。在某些实验中，在波带片的上游放置一个预针孔（10-100μmφ），以提供相干照明，针孔的对准借助于压电驱动的十纳米精度的工作台来实现。在日本筑波光子工厂的BL-12 A和BL-11 A光束线上获得了波长分别为1.5nm、2.4nm和3.6nm的单色软X射线。从由一定宽度的线和空间组成的测试图形上的线间距的分辨率来判断，用10μmφ的预针孔和1μmφ的针孔组合获得了0.2-0.3μm的最高空间分辨率。利用该系统，我们获得了EM网格，干燥的哺乳动物细胞和干燥的人类染色体的图像。哺乳动物细胞中的颗粒结构和染色体中的精细结构被区分开来。在图像采集的同时，进行了计算研究，以1）评估波带片和针孔的组合的光学特性，以及2）开发用于改善从实验获得的由菲涅耳衍射失真的图像恢复的图像的质量的方法。该系统在以下方面的进一步改进：1）分辨率的提高; 2）湿环境中生物样品成像的发展; 3）通过计算机处理提高图像质量，以及其医学/生物应用仍有待研究。

Soft X-ray projection microscopy using synchrotron radiation as a light source has been developed. The system consists of a Fresnel zone plate with an outermost zone width of 80nm, a pinhole (0.5-20μmφ), specimens on a specimen holder, and a back-illuminated CCD camera. In some experiments, a pre-pinhole (10-100μmφ) was placed in the upper stream of the zone plate to give coherent illumination to it. The alignment of the pinhole was achieved with the aid of piezo-driven stages with ten-nanometer precision. Monochromatic soft X-rays of the wavelengths of 1.5nm, 2.4nm and 3.6nm were obtained from the beamline BL-12A and BL-11A at the Photon Factory, Tsukuba, Japan. The highest spatial resolution of 0.2-0.3μm was attained with the combination of a 10μmφ prepinhole and a 1μmφ pinhole, judging from the resolution of line spacing on a test pattern consisting of lines and spaces with defined widths. With this system, we obtained images of EM-grids, dried mammalian cells, and dried human chromosomes. Granular structure in mammalian cells and fine structure in chromosomes were distinguished. In parallel with the image acquisition, computational studies were conducted 1) to evaluate optical properties of the combination of a zone plate and a pinhole, and 2) to develop the method for the improvement of the quality of images recovered from the experimentally obtained images distorted by the Fresnel diffraction. Further improvements of the system in 1) the improvement of the resolution, 2) the development for imaging biological specimens in wet environment and 3) the improvement of the quality of images by a computer processing, and its medical/biological application remained to be studied.