By Simon Makin

If breast cancer is caught early, its survival rate is nearly 100 percent. If not, that rate can quickly drop to roughly 25 percent. Women older than 50 in the U.S. are advised to get mammograms every two years, but the most aggressive tumors often arise and are diagnosed between screenings.

These “interval” cancers account for around a quarter of all breast cancer cases, “and by the time you're diagnosed, it [may be] too late,” says Canan Dagdeviren, a materials engineer at the Massachusetts Institute of Technology. So Dagdeviren and her team have developed a wearable ultrasound scanner that could be used at home to detect breast tumors earlier, particularly in high-risk people. “Frequent screening is the key for survival,” she says.

Conventional—and bulky—ultrasound scanning machines use piezoelectric materials (which convert electrical signals into movement) to send out sound waves that penetrate the body. Denser tissue reflects more sound, signaling the presence of a tumor. Dagdeviren says she and her team miniaturized a scanner using a new type of piezoelectric material that performs better and requires less power. “You get better penetration of deep tissue, using lower voltage,” she says.