Volume 10, Number 1 • January/February 2002 • Small Business/SBIR

Making X-Rays Better

Reverse geometry X-radiography (RGX) was developed by Digiray, Corp., using two NASA Small Business Innovation Research (SBIR) program awards.

Reverse Geometry X-radiography improves image clarity to the extent that (left) the thin latex glove on the hand, as well as bone details can be seen. At right, teeth and jaw imaging benefit from high contrast resolution. Photos courtesy of Digiray, Inc.

Unlike conventional x-ray systems, which place the radiographic object close to the large-area detector, the Digiray system places the radiographic object close to the x-ray source. A point detector then captures the primary radiation without the image-degrading secondary radiation inherent in standard x-ray systems.

Another fundamental difference between the two radiographic processes lies in the performance characteristics of the imaging detectors. Digital images are produced by Digiray’s system using a scintillating crystal with a dynamic range at least 10 times superior to film. This digital image can then be enhanced by a wide variety of standard image-processing tools such as averaging, filtering, image subtraction and edge enhancement.

Using the SBIR awards, managed by NASA Langley Research Center (LaRC), Digiray enhanced the RGX system by modifying its x-ray tube to increase its penetrating capability from 100 kilovolts to 150 kilovolts and then, in the second award, proceeded to develop a portable x-ray system. In November 2001, a highly successful new test was performed on a Boeing 707 at an airfield in Melbourne, Florida using a dual robot. The detector array was mounted on one part of the robot and the x-ray source on the other. This is the first automated application for the RGX.

Digiray’s patented reverse geometry laminography (RGL™) system is a result of the company’s efforts to increase the x-ray energy of the RGX system. The RGL system provides layer-by-layer x-ray viewing with one x-ray exposure. The precision of Digiray’s single exposure RGL system is demonstrated by its ability to provide separate head and tail coin images with one x-ray exposure. The resolution and gray scale performance of the laminography was recently improved according to Dr. Richard Albert, president of Digiray, by increasing the number of detectors from the eight used in the previous array to 64. The clarity of RGL may provide x-ray imaging for medical applications including mammography, cardiac imaging, brain surgery and orthopedics.

“Additionally, initial efforts are under way to develop x-ray diffraction,” Albert said. “An operational prototype has been developed which gives complete texture determination with very high throughput.” A patent was recently issued for this RGXRD™ system.

Commercialization of the RGX system is now in progress. Systems have been sold to Japan, the United Kingdom, Saudi Arabia, the US Air Force and LaRC, among others. In addition, said Albert, a motionless CT system is being tested for a medical or dental application in a joint program with the University of Southern California. Q

For more information, contact Dr. Richard Albert at Digiray, Inc., info@digiray.com. Please mention you read about it in Innovation.

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