Stanford University researchers think they are four to five years away from a handheld, cancer-detecting device.

Nancy Crotti

Ever since Dr. Leonard "Bones" McCoy first waved his "tricorder" over a patient to diagnose an illness or injury on Star Trek, earthlings have longed for such a powerful medical device. Researchers at Stanford University say they're on track to produce one.

The device uses heat and sound waves to detect objects embedded beneath surfaces, such as improvised explosive devices and tumors inside human bodies. The radio frequency/ultrasound hybrid imaging system uses airborne capacitive micromachined ultrasonic transducers (CMUTs) to detect objects in "highly dispersive media," such as water, soil and tissue, according to an article published in the journal Applied Physics Letters and presented at the International Ultrasonics Symposium in Taipei, Taiwan.

The project was spurred by a challenge by the Defense Advanced Research Projects Agency (DARPA) to develop a system to detect plastic IEDs, which are invisible to metal detectors. The system also could not touch the ground, because that might lead to detonating the bomb.

The device operates under the principle that materials expand and contract at different rates when heated. Ground, especially muddy ground, for example, absorbs more heat than plastic.

It uses microwaves to heat the area, causing the mud to expand and squeeze the plastic. Pulsing those microwaves cangenerate a series of ultrasound pressure waves that CMUTs can discern jumping from the solid through the air to the detector, revealing the presence of buried plastic explosives, explained a statementfrom Stanford.

On the medical side, these CMUTs could use ultrasound waves to "hear" tumors growing inside a body, according to one of the researchers, Stanford engineering research professor Butrus Khuri-Yakub.

Khuri-Yakub and his colleague, Assistant Professor Amin Arbabian principally work in medical research. They decided to apply the results of the DARPA challenge to the problem of detecting early-stage cancer without touching the skin. Their technology is part of what's behind the imaging system developed by Butterfly Network, a four-year-old company seeking to transform diagnostic and therapeutic imaging, Khuri-Yakub added.

"It's sort of natural to develop a technology and to move on into the medical state," he said. "As engineers, we have hammers. We're looking for nails."

The research team used brief microwave pulses to heat a flesh-like material that had been implanted with a sample "target." Holding the device from about a foot away, they heated the material by a thousandth of a degree. The material expanded and contracted, creating ultrasound waves that they were able to detect, disclosing the location of the target without touching the "flesh," just like the Star Trek tricorder.

The team has been working on this for about two years, and could have results that use a hand-held device to detect cancer in four to five years, according to Khuri-Yakub.

The initial research has generated enough public interest that Khuri-Yakub and his associates have been meeting with colleagues in the Stanford School of Medicine to discuss next steps. They're also aggressively pursuing research dollars from private and public sources.

"We're trying to push the pedal to try to raise funding as opposed to only writing an NIH proposal," he said. "The interest has sent our way some individuals who are interested in funding. We have to look at it more closely. 

Nancy Crotti is a contributor to Qmed and MPMN.

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