Stanford engineers develop ultrasound device to deep-scan objects, tumors

Researchers at Stanford University have unveiled a new technology that can locate non-metal objects and abnormal tissue growth within the human body while providing an accurate mapping of the target.

The technology, detailed this week in the journal Applied Physics Letters, was designed by assistant professor Amin Arbabian and research professor Pierre Khuri-Yakub with the Electrical Engineering Department at the school in North California, on the U.S. west coast.

With a fellowship granted by the U.S. Defense Advanced Research Projects Agency (DARPA), both researchers initially worked on a project to find possible ways to detect buried plastic explosive devices.

DARPA had one request: any device designed by the team could not touch the surface of the scanned object, for fear that it could trigger an explosion. With this caveat in mind, the team decided to harness the power of microwaves, which give out characteristic ultrasounds when the materials are heated up.

All materials expand and contract when stimulated with electromagnetic energy, thus producing ultrasound waves that travel to the surface and can be detected remotely.

Arbabian told Xinhua that the "main problem was the fact that touching the surface of the objects was not allowed," making ultrasound less effective as many of the waves are lost as they pass through the air. As a solution, the team used wave detectors known as "capacitive micromachined ultrasonic transducers" that are sensitive enough to pick up weak ultrasound signals coming from any buried object.

"When we saw it work," Arbabian said, "we decided to test it from a medical side and see if we could use the same technique to detect tumors." Using slight heating, safe for the human body, he and his colleagues were able to locate a target after it expanded and contracted, releasing ultrasound waves.

"We are now able to provide precise mapping of any buried object, be it under the ground or inside the flesh," he said.

The team foresees this technology being used in an array of medical situations, such as helmets to locate brain hemorrhages, or to spot injuries in a soccer match.

One of the advantages, Arbabian said, is that the gadget can be portable as it is roughly the size of a briefcase. The aim is to shrink it as much as possible, so it can be fixed on a smartphone. But, since they need to test it on humans before it is approved by the U.S. Food and Drug Administration, the team believes the device will not go mainstream until at least a decade from now. Endi