Biomedical Imaging

该项目使用成像科学技术来分析许多类型的生物，临床和生物医学图像。目前的研究主要集中在三个领域：（1）使用电子显微镜和NMR光谱的图像处理的大分子结构生物学;（2）生物医学和实验室成像;（3）计算算法和3D重建方法的开发。 (1)成像科学实验室与各研究所开展了一项重大的合作研究工作，涉及在结构生物学中使用图像处理技术和先进的计算技术，以分析电子显微照片和核磁共振光谱，目的是确定大分子结构。近年来的研究主要集中在二十面体病毒衣壳的三维重建、分析和解释上。正在进行的研究涉及与疱疹病毒以及其他二十面体病毒衣壳相关的结构分析。今年，我们确定了疱疹病毒衣壳的绝对手性，并分析了原衣壳到成熟衣壳的形态发生。我们一直在开发生物分子NMR结构测定的计算工具。在完成了一项协议，允许NIH重新分配Xplor-NIH生物分子NMR结构测定包，我们已经实现了一个通用的基础和编程接口的Python和TCL语言绑定到Xplor-NIH包。我们实现了一种算法来可视化生物分子结构的大集合。我们已经开发了自动分配核奥弗豪泽效应谱的方法。最后，我们为NIH内外的团体提供了Xplor-NIH包的持续支持。 (2)成像科学实验室致力于为NIH的各种临床和生物医学活动提供计算和工程专业知识。具体而言，PET、超声、CT、MRI、EPR、显微镜、癌症研究中的成像以及与神经功能障碍相关的成像已经以多种方式得到支持。为了支持NIH内部计划的科学研究，CIT在开发一个独立于平台的、n维的、通用的、可扩展的图像处理和可视化程序方面取得了重大进展，该程序用JAVA编程语言编写。MIPAV（医学图像处理分析和可视化）应用程序可以对多种模态的医学图像进行定量分析和可视化。它已被用于诊断放射学分析肿瘤，与NIDCR合作协助纵向研究，分析NIMH的MRI图像，并已被NCI用于2D显微镜样品的分析。最近，我们（与NEI合作）将MIPAV改编为外科医生的工具，以帮助评估黄斑变性的治疗方案。 (3)在计算算法和3D重建方法的发展，我们继续适应我们以前的3-D PET重建算法的新一代廉价的小动物PET扫描仪（阿特拉斯系统），由像素化闪烁晶体的相对阵列。由于这些像素化扫描仪适用于大批量小动物研究，我们开发了客户端-服务器软件，以促进CIT高性能计算集群上的生产模式重建处理。我们参与开发新的动物PET扫描仪技术，使图像分辨率远远超出了以前最先进的扫描仪。我们还开发和实现了EPR重建的迭代算法，包括乘法算术重建技术（MART）和最小二乘/熵最大化算法。预计交付的CTI高分辨率研究断层扫描仪（HRRT）的NIMH分子成像分支，我们已经开始设计一个完整的实施最大似然重建重建算法，这将包括精确校正所有的物理效应，包括运动，散射，和深度的相互作用的晶体。HRT在临床PET系统中是独特的，因为供应商不提供用于执行常规重建的完整软件，部分原因是与处理采集数据相关的许多未解决的研究问题。

This project uses imaging science techniques to analyze many types of biological, clinical and biomedical images. Current research focuses on three general areas: (1) the structural biology of macromolecules using image processing of electron micrographs and NMR spectroscopy; (2) biomedical and laboratory imaging; and (3) computational algorithms and 3D reconstruction methods development. (1) The Imaging Sciences Laboratory has a major collaborative research effort with the Institutes involving the use of image processing techniques and advanced computational techniques in structural biology to analyze electron micrographs and NMR spectra with the goal of determining macromolecular structures. Recent efforts have concentrated on the 3D reconstruction, analysis and interpretation of the structures of icosahedral virus capsids. Ongoing research involves analyses of structures related to herpesvirus as well as other icosahedral virus capsids. This year we determined that absolute handedness of herpesvirus capsids and have analyzed the morphogenesis of the procapsid to the mature capsid. We have been developing computational tools for biomolecular NMR structure determination. Having completed an agreement with the Accelrys corporation which allows NIH to redistribute the Xplor-NIH biomolecular NMR structure determination package, we have implementated a general foundation and programmatic interfaces for Python and TCL language bindings to the Xplor-NIH package. We implemented an algorithm to visualize large ensembles of biomolecular structures. We have developed methodology to automatically assign nuclear Overhauser effect spectra. Finally, we have provided ongoing support of the Xplor-NIH package to groups within and outside of NIH. (2) The Imaging Sciences Laboratory has a commitment to providing computational and engineering expertise to a variety of clinical and biomedical activities at NIH. Specifically, PET, ultrasound, CT, MRI, EPR, microscopy, imaging in cancer research, and imaging related to neural disfunction have been supported in a number of ways. To support scientific research in the NIH intramural program, CIT has made significant major progress in the development of a platform-independent, n-dimensional, general-purpose, extensible image processing and visualization program written in the JAVA programming language. The MIPAV (Medical Image Processing Analysis and Visualization) application enables quantitative analysis and visualization of medical images of numerous modalities. It has been used to analyze tumors for Diagnostic Radiology, assisted in longitudinal studies in collaboration with NIDCR, analysis of MRI images for NIMH, and has been used by NCI for the analysis of 2D microscopic samples. Most recently we have (in collaboration with NEI) adapted MIPAV to be used as a surgeon's tool to assist in the evaluation of a treatment protocol for macular degeneration. (3) In computational algorithms and 3D reconstruction methods development, we have continued to adapt the our prior 3-D PET reconstruction algorithms for a new generation of inexpensive small animal PET scanners (the Atlas system), consisting of opposed arrays of pixelated scintillation crystals. Since these pixelated scanners are suitable for high-volume small animal studies, we have developed client-server software to facilitate production mode reconstruction processing on CIT's high performance computing cluster. Our participation in the development of new animal PET scanner technology has extended image resolution far beyond what was available from previous state-of-the-art scanners. We have also developed and implemented iterative algorithms for EPR reconstructions, including the multiplicative arithmetic reconstruction technique (MART) and a least-squares/entropy maximization algorithm. Anticipating the delivery of the CTI High Resolution Research Tomograph (HRRT) to the NIMH Molecular Imaging Branch, we have begun the design of a complete implementation of maximum-likelihood reconstruction reconstruction algorithms which will include accurate corrections for all physical effects including motion, scatter, and depth-of-interaction in the crystals. The HRRT is unique among clinical PET systems in that the vendor does not provide complete software for performing routine reconstructions, due in part to the many unresolved research questions associated with processing the acquired data.