Anyone who’s ever had a mammogram knows the understatement in the words “You may feel a little discomfort.” Anyone who’s had a false positive result from a mammogram knows the panic that quickly displaces the discomfort. But most women also know that adding mammograms to clinical exams is the best detection system there is for breast cancer—a life-threatening disease diagnosed in 192,000 American women each year. What most people don’t know is that today’s mammograms miss 15 to 20% of breast tumors.

There may soon be an alternative to conventional mammograms, providing much sharper, more detailed imaging, thanks to a team of researchers coordinated by NC State professor of physics Dr. Dale Sayers. The new approach would require significantly less compression of the breast during imaging, removing women’s biggest deterrent to regular screening.

The new process, called Diffraction Enhanced Imaging (DEI), shows 8 to 14 times more contrast than conventional radiographs (see figure). It uses a single-energy fan beam of x-rays instead of the broad-energy beam of conventional radiography. An analyzer crystal is placed in the x-ray beam between the film and the object being studied, diffracting a particular wavelength of x-ray through the physics principle known as Bragg’s law. The resulting image shows changes in x-ray refraction as the beam passes through the target, and highlights the edges of tissue structures.

Sayers started working on the project eight years ago with Drs. William Thomlinson and Zhong Zhong (scientists at the Brookhaven National Synchrotron Light Source), Dr. Dean Chapman (formerly at Brookhaven and now at Illinois Institute of Technology), and Dr. Etta Pisano (Chief of Breast Imaging at the UNC School of Medicine). At UNC, Pisano and NC State alum Dr. Chris Parham are clinically validating the technology for breast imaging, comparing conventional digital x-ray images of biopsy tissue samples with DEI images of the same samples, and designing future in vivo studies.

Thomlinson, Zhong, and Chapman invented the concept using the $100 million Brookhaven synchrotron light source, but a portable version must be developed for clinical use if DEI is
to replace conventional mammograms. Assisted by students, Sayers and NC State nuclear engineers Kuruvilla Verghese and Mohamed Bourham are using computer models to understand the science of DEI, develop a clinical prototype, and work on other possible applications. Sayers contends that if the prototype works, it would work for many applications, especially in contrasting lung tumors from foam-like lung tissue.

“It’s not often that an atomic physicist gets to apply results directly to patients,” says Sayers. “But if DEI can be applied at the clinical level, it has the potential of replacing mammograms as a clinical tool, finding tumors earlier, reducing false positives and negatives, and saving many lives.”

Sayers’ recently received the International X-ray Society (IXS) Outstanding Achievement Award for his career achievements in developing the field of XAFS (X-ray Absorption Fine Source), a major imaging tool used around the world for the past 20 years. The XAFS technology and process, which led to Sayers’ work with DEI, helps to better understand atomic level structure of complicated materials.