FOR IMMEDIATE RELEASE
Feb. 24, 2000
North Carolina State University
News Services
CB 7504
Raleigh, NC 27695
(919) 515-3470
[email protected]
http://www.ncsu.edu/news
Media Contacts:
Dr. Dale Sayers, NC State, [email protected]
Dr. Etta Pisano, UNC-CH, 919/966-6957 or [email protected]
Tim Lucas, NC State News Services, 919/515-3470 or [email protected]
David Williamson, 919/962-8596 or [email protected]
Studies Show New Imaging Technique Improves X-rays of Breast Tissue
A research team led by scientists at the University of North Carolina at Chapel Hill and North Carolina State University has developed a new X-ray imaging method that produces significantly better pictures of breast tissue than conventional X-rays and could make mammography more effective in revealing tumors.
The research team, led by Dr. Etta Pisano, professor of radiology at UNC-CH School of Medicine, and Dr. Dale Sayers, professor of physics at NC State, is developing what it calls Diffraction Enhanced Imaging (DEI).
Other institutions involved include Brookhaven National Laboratory's National Synchrotron Light Source, the Illinois Institute of Technology (IIT) and the European Synchrotron Radiation Facility in Grenoble, France.
A report on the latest research appears in the March issue of Radiology. Besides Pisano and Sayers, the paper's authors include NC State graduate student Miklas Z. Kiss.
"The images we have, which are the first to be published using this new DEI technology, are just spectacular," says Pisano.
"Once we've overcome some technical challenges and adapted it for clinical use, DEI conceivably could be used not only in breast imaging, but in any medical and non-medical application involving X-rays. The sky's really the limit," she says.
"From a personal perspective, I've been excited by the potential for DEI to revolutionize X-ray imaging," Sayers says. "If the next phases of our work are successful, then in 10 to 20 years, it is possible that almost every X-ray imaging apparatus in the world would be replaced by a DEI
apparatus."
The new research involved creating images of seven breast cancer tissue specimens at Brookhaven using the DEI technique and conventional digital X-ray images at UNC-CH. Researchers then carefully compared the images and found tumor visibility was superior with DEI in six of the seven specimens. Pathologic studies, showing that the increased detail reflected real structural information about tumors and was not manufactured by the technique itself, confirmed the results.
DEI differs from traditional X-ray radiography in that an "analyzing" crystal is placed in the X-ray beam between the object being studied and an image-creating medium such as film, X-ray plate or digital detector, Sayers says. The silicon crystal diffracts a particular wavelength
of X-ray through a physics principle known as Bragg's law.
When the crystal is adjusted and two images taken and processed, the result is one image based on X-ray absorption that is similar to a standard X-ray and a new image based on refraction, he says. Refraction is a process where light, including X-rays, deviates in angle slightly -- something like a ricochet -- because of differences in the atomic density of the materials it passes through.
"In a tissue sample, if a tumor is embedded in normal tissue there's usually a density difference that results in the defraction, which is detected and imaged and has now been shown to be more sensitive in some cases for features diagnostic of cancer," Sayers says.
Pisano said the team still has a long way to go before they have a practical machine that can be used clinically but the researchers believe they are closing in on a big advance in medicine. "Obviously we can't bring everybody to the world's few synchrotrons for routine mammography, and so we have to make this technology clinically portable," she says. "Right now we think that's doable."
Synchrotrons, like the one at Brookhaven, are large accelerator machines that speed up atomic particles such as electrons and positrons to create electromagnetic radiation useful in various ways.
The U.S. Army, the U.S. Department of Energy and the State of Illinois Higher Education Cooperation Agreement have supported the research, which began more than seven years ago.
Other co-authors on the Radiology paper are Drs. R. Eugene Johnston, David B. Washburn, Mary V. Iacocca and Chad Livasy of radiology and pathology at UNC-CH; Dr. Dean Chapman of IIT, Dr. Joseph Geradts of Oxford University; Dr. Zhong Zhong of Brookhaven; and Dr. William Tomlinson of the European Synchrotron Radiation Facility.
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