Handheld t-ray -- it’s not your dad’s radiology

February 23, 2007

The last time medicine had a new “ray” was back when radioactivity was king, spawning nuclear medicine and grade-B sci-fi flicks. Before the gamma ray was the x-ray . . . and that goes way back.

The last time medicine had a new "ray" was back when radioactivity was king, spawning nuclear medicine and grade-B sci-fi flicks. Before the gamma ray was the x-ray . . . and that goes way back.

So it is with some excitement that I am now reading about the t-ray. This relatively unused photon hails from a region of the electromagnetic spectrum between infrared and microwave, the terahertz region, with frequencies from 0.1 to 10 terahertz. And there's plenty to get excited about.

T-rays don't pose the same health risks as x-rays. Unlike ultrasound, terahertz transmitters don't have to contact the skin to send those rays into the body. And, like MR, t-rays can gather spectroscopic information about the composition of materials, especially in biological tissues.

A sobering fact, however, is that this region of the electromagnetic spectrum is not so much new as it is unused. Scientists have been fiddling with it for more than 20 years. A big hitch in efforts to get t-rays into practical use, any practical use, has been the size and weight of t-ray generators, which have been built around high-powered lasers that are very heavy, very big, and very expensive.

That's where Brian Schulkin comes in. A doctoral student in physics at Rensselaer Polytechnic Institute, Schulkin has developed a handheld terahertz spectrometer that he calls the Mini-Z.

It's been used already to detect cracks in space shuttle foam, spot counterfeit watermarks on paper currency, and image tumors in breast tissue, according to RTI. The system weighs less than five pounds and is small enough to fit in a briefcase. With the weight and size issues out of the way, only one problem remains: the fact that t-rays represent a disruptive technology. And that, right off the bat, is strike one against it.

Disruptive technologies don't fare well in medicine. When they do break into clinical practice, they usually take a long time to be accepted, and, even then, conditions have to be just right. Take PET, for instance, the last disruptive technology to gain a foothold in medical imaging. More than two decades passed from the time the first image was made at Washington University in the 1970s until PET became widely available.

It can't be argued that medical imaging lags far behind other industries in the adoption of new technologies. Part of it, certainly, is the regulatory hoops through which manufacturers must jump. But what constitutes the rest of the wall over which new ideas must be thrown to enter medical practice? What is it that keeps new ideas out? And what can be done about it?

Answers to these questions could have as much impact on the practice of medicine and the evolution of medical imaging as the handheld Mini-Z . . . maybe more.