For immediate release: April 21, 1998

Contact: Alicia Conroy (781) 736-4203

Detector Technology Leads to High-Resolution
Digital Breast Imaging Device

Waltham, Mass. -- An X-ray detector technology first developed for use by structural biologists is now being used to produce speedy, high-resolution digital images of breast tissue that could replace standard mammograms as a screening technique.

The Digital Mammography Group at Brandeis University's Rosenstiel Basic Medical Sciences Research Center recently completed its first set of clinical trials at the University of Virginia using a prototype imaging device. The resulting images are produced in a few seconds and show much better detail and resolution compared to the standard mammogram. Better quality images could lead to earlier detection of changes in tissue that might indicate cancer. About 20 percent of breast tumors are missed by conventional mammograms, and the difficulty of detecting them increases in younger women whose tissue is more dense. When tumors are found at the earliest stage of growth, the survival rate is close to 100 percent.

There are other digital breast imaging projects in development, but the Brandeis group is using a different technology, says principal investigator Martin Stanton, Ph.D., who is trained as a biophysicist and biochemist. He and Walter Phillips, Ph.D., had developed new detectors for use in X-ray crystallography, and saw the potential for clinical use.

"We're drawing on different processes for breast imaging," says Stanton. "In addition to speed and improved resolution, these developments open the door to novel imaging techniques. We're exploring three-dimensional resolution, and there's the potential to expand into nuclear medicine techniques using contrast agents, and other areas."

The imaging project is supported by the National Cancer Institute of the National Institutes of Health. The group is currently negotiating to hold the next clinical trials for the digital imaging device prototype at a major Boston teaching hospital. From Proteins to People: Detectors Harnessed for Diagnostics

The new imaging process draws on technology developed for structural biology experiments, in which Stanton's group has been a world leader. Fifteen years ago, biophysicists used X-ray diffraction crystallography with weak X-ray sources and film to capture images of the atomic structure of crystallized molecules like small proteins. Stanton and Phillips began their quest to design a higher-powered X-ray detector that would be more precise and take less time to use.

Others developed detectors using image plates coated with substances that store the diffracted image, which is "activated" when scanned by a laser. Stanton and his colleagues instead used a charge-coupled device (CCD), which converts the light impulses into electric impulses that can be saved digitally. A detector using an image plate can take 3 to 10 minutes from the beam impulse until an image is produced; a CCD takes two seconds.

That detector technology is essentially the same in the digital breast imaging device. X-rays pass through the tissue and are converted into light by a phosphor screen. This light is then funneled by a fiber-optic taper to a CCD, which produces an electronic image that is relayed to a computer, which assembles it into a seamless image, carries out image enhancements, and provides output to film on demand. The high-resolution images of the Brandeis team's prototype device are 6000 x 4000 pixels, with a high dynamic range ("gray scale"). The output can be viewed on a computer screen or printed to film for examination by a radiologist.

Even before its foray into clinical applications, the Brandeis group was considered cutting-edge, and has created X-ray detectors for large-scale scientific use including at the Brookhaven (N.Y.) and the Argonne (Ill.) national laboratories.

For more information on Marton Stanton's research, click here.