These are excerpts from an article in Scientific Computing & Automation magazine, February, '97 issue.

Until now, it has been a simple fact of life. Medical doctors must work in three dimensions. Medical images generated by CT scans and MRI are captured in two dimensions. "In their minds, doctors have had to reconstruct and consolidate the cross-sectional images into 3-D models." said Ronald Summers, M.D., and Ph.D., a clinical radiologist in the diagnostic radiology department at the National Institute of Health in Bethesda, MD.

That is starting to change. While completing a fellowship at Duke University, Summers saw a demonstration of a "virtual colonscopy," in which the presenter used virtual reality techniques to examine the colon. "I saw that the approach had real potential for non-invasive diagnostic," Summers said.

The output from the MRI and CT scanners Summers and his colleagues routinely use is uploaded to the Internet. From there, the data sets, which range from 70 Mb to 120 Mb are downloaded to Summers' SGI workstation. Summers strips the header information and generates a 3-D uniform lattice to use as input for the software. "With the 3-D model and the Fly Viewer, I can move around and look for lesions of the bronchial wall. I can also look for areas of narrowing, and I can make measurements of bronchial size," he said. "The measurements cannot be made accurately with the bronchoscope used in the standard procedure because the angle is too wide."

In addition, to "flying through" the data on the screen, Summers can capture the visualization on standard VHS videotape or create 35 mm slides for presentation.

There is no doubt that 3-D visualization presents a compelling visual display of the medical image data. "It is spurring us to think about diagnostic images in a new way". "The key is getting more information out of the data."