New x-ray technique may aid mammography.

By creating significantly sharper, more detailed pictures of breast tissue, a technical advance in radiography dramatically could improve mammography and other medical and materials imaging. The ultimate goal will be to cut the number of breast cancer deaths by diagnosing tumors earlier. A team of scientists from the University of North Carolina at Chapel Hill; the Illinois Institute of Technology, Chicago; Brookhaven National Laboratory, Upton, N.Y.; and North Carolina State University, Raleigh, are developing the new imaging method using a single-energy X-ray source. Such sharply defined pictures never have been produced through conventional X-ray machines.

"Mammography presents difficult imaging problems because the densities of the tissues are similar and the lack of contrast often masks tumors," indicates Etta Pisano, associate professor of radiology at the University of North Carolina School of Medicine. "With our new method, which we call defraction-enhanced imaging, or DEI, we have produced images showing improved detail of cancerous tumors in human breast tissue. The detail is just outstanding--it's like casting a sharper shadow when the sun shines down on you. While much work remains to be done before we can use this with patients, we are absolutely excited about the possibilities. This has never been done before, and we know of no reason why it couldn't work on other parts of the body as well."

In conventional mammography, differences in tissue densities and composition are shown through absorption as contrasting areas in the image, allowing doctors to see tumors or changes in tissue. The problem is that differences between healthy and cancerous tissues are very small, and X-ray scattering can lead to lower contrast...