9317816 Ritman The objective of this proposal is to fabricate and evaluate a prototype volume imaging x-ray micro-CT scanner (augmented by novel tomographic image reconstruction, 3D image analysis and display software) for application to biological specimens. The scanner design is inspired by a unique micro- CT scanner developed by a research group of the Exxon company for their geological purposes. Members of the Exxon Research team will provide consultations needed for duplication of important aspects of their scanner. This new capability has great potential for providing quantative insights into how mechanisms at the cellular level integrate to express themselves in the anatomy of organs at the micro and macroscopic scale. This proposed scanner will generate volume images of at least 5123 cubic voxels (10 to 40m on a side). This scanner extends current micro-CT methods, developed primarily for material sciences and nondestructive testing purposes, by imaging larger volumes with greater spatial resolution, within a reasonable period of time. This is an improvement over optical microscopic and conventional x-ray magnification techniques in that the logistics of image data analysis are greatly improved. The reason a computed tomographic imaging approach (which eliminates re-assembly of one-at-the-time scanned slices) and because we have already developed software for quantitative analysis and display of the 3D volume images. This software can be readily expanded to handle the huge 3D images (e.g., up to 109 voxels) to be generated with the proposed scanner. Several software approaches, which we have developed in recent years for 3D whole body scanning CT image data, should greatly extend the power of the x-ray micro-CT methodology as follows: a) Ability to scan objects greater than the size of the fluorescent screen because we can use the 'local' (as compared to the conventional 'global') reconstruction algorithm that our collaborators Drs. Faridani and Smith of Oregon State University have developed. This algorithm needs to 'see' only the projection through the volume of interest within a larger specimen. Consequently organs within the intact body of small animals can be scanned without the need to scan the entire transverse anatomic extent of the body, thereby greatly reducing scanner cost. b) Another new algorithm has been developed by Dr. Faridani that may provide almost double the spatial resolution "allowed" by the traditional relationship between numbers of angles-of-view and numbers of samples along the transverse x-ray absorption profile. c) Ability to automatically segment large and complex 3D images such as the entire arterial trees with its thousands of branches, using an algorithm of the type developed by Dr. Higgins of Pennsylvania State University. d) Ability to automatically analyze the segmented vascular trees for segmental dimensions and branching angles using modified versions of the algorithms and image analysis software developed in our laboratory for analysis of macrovascular arterial tree geometry.
