Overview

Reconstruction of Serial Section (ROSS) was developed at the Center for Bioinformatics at NASA Ames Research Center. It is a platform-independent software package that can visualize objects stereoscopically and interact with virtual environments. It can be used in conjunction with other software and libraries, including multiresolution methods, OpenGL, and Open Inventor for manipulating bone or tissue segmented by the ROSS cutting tools, the CyberScalpels.

It was originally designed for the analysis of transmission electron microscope (TEM) images in space research. ROSS includes automated and interactive segmentation algorithms and all other functions are fully automated. When possible, automated segmentation is based on gray-scale thresholding and contours are connected with an algorithm based on splines.

ROSS has been applied to DICOM formatted CT scans since for these images thresholding is quite effective (see Fig. 16). It has also been used with spiral MRI scans of the breast and with ecocardiographic data to show the Doppler effects in a beating heart. ROSS can implement volumetric segmentation followed by a variation of the Marching Cubes algorithm for mesh generation. Three frames of a beating heart sequence are shown in Fig. 17. A training guide, called Mesher, for visualizing the face and skull from CT scans of the Visible Human Female (NIH) is available.

The Center for Bioinformatics at NASA Ames Research Center conducts research to provide interactive virtual environment imaging capabilities for use at remote sites, such as the International Space Station, the moon, or Mars. Such applications require visualizing surfaces that have more than a million polygons at various levels of resolution without loosing topographical features. This multiresolution technique has been applied to ROSS images using off-the-shelf methods such as QSlim (Michael Gardner; http://www.cs.cmu.edu/ ~ garland/). This allows images to be manipulated in real time on a personal computer, or transferred faster through links at remote sites (see "Telemedicine" on http://biocom-p.arc.nasa.gov).

Subroutines called CyberScalpels increase the potential for interaction in virtual environments from local or remote sites. One CyberScalpel can be used to cut layered tissue or flat bones of the skull while the other bisects long bones, the jaw, and rounded or irregularly shaped tissue and organs. Haptic feedback for the cutting tool software is under development using real-time mesh deformations with force feedback. These developments, miniaturized immersive virtual environments on PCs and 3D monitors that require no special glasses, are expected to serve in medical, space, and other scientific applications as well as industrial practices in the future.

FIGURE 18 MRI scan of head displayed by Slicer Dicer. Transparency threshold is adjusted to show the skin-air interface. Two cutouts and a coronal slice are present. (Data courtesy of Siemens Medical Systems, Inc., Iselin, NJ, and the SoftLab Software Systems Laboratory, University of North Carolina.)

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FIGURE 18 MRI scan of head displayed by Slicer Dicer. Transparency threshold is adjusted to show the skin-air interface. Two cutouts and a coronal slice are present. (Data courtesy of Siemens Medical Systems, Inc., Iselin, NJ, and the SoftLab Software Systems Laboratory, University of North Carolina.)

FIGURE 19 CT scan of head displayed by Slicer Dicer. Transparency threshold is adjusted to show the skull. A cutout is used to remove a portion of the skull, revealing structures inside. Three projected volume images are rendered on the background walls. (Data courtesy of the National Library of Medicine, U.S. Department of Health and Human Services.)

FIGURE 19 CT scan of head displayed by Slicer Dicer. Transparency threshold is adjusted to show the skull. A cutout is used to remove a portion of the skull, revealing structures inside. Three projected volume images are rendered on the background walls. (Data courtesy of the National Library of Medicine, U.S. Department of Health and Human Services.)

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