Markers like these in a CT scan can help scientists determine what genes are active in liver cancer.

Image: Michael Kuo/UCSD Department Of Radiology Two recent scientific discoveries mark the latest steps toward the ultimate medical-diagnosis technology: the tricorder.

Bones McCoy made Star Trek's portable black box famous by using it to diagnose ailments without ever touching a patient. Now, studies show that the tricorder is closer to becoming reality, because of new medical-imaging technology and a new state of matter.

"When we were conceptualizing (our experiment), we saw the ultimate device should be noninvasive, giving you the molecular details of the disease going on inside the body," said Howard Chang of Stanford University's Comprehensive Cancer Center. "I think a tricorder is a useful idea.... It shows the gap between what we have now and what we hope technology will achieve in the end."

Scientists have been trying to construct a tricorder-like device for years, but no one has managed to pack all the functions of a true tricorder – point, pull a trigger and diagnose – into one handheld unit.

Last year, Purdue University researchers unveiled a shoebox-size molecular scale that can chemically weigh everything from tumor markers in urine samples to potential explosives residue on luggage. Attempts at replicating the tricorder's geographic omniscience have recently been chronicled. And in 1996, a Canadian company surfaced long enough to stamp the name Tricorder on a handheld electromagnetic sensor and weather station.

Combining the technologies into one compact box may take decades. But the two latest discoveries offer incremental advances in diagnostic medicine – pointing toward more portable and less invasive medical technologies.

Several lab-on-a-chip technologies have brought diagnosis to handhelds, but they still require a tissue sample. Chang's group has developed a way to observe gene activity without so much as a cheek swab. Another advance could lead to portable imaging technology as powerful as machines that today occupy entire rooms.

Chang and his co-authors have linked visible patterns in computed tomography, or CT, scans of liver-cancer patients with cancer-gene activity.

"(We're) trying to put a patient in a CAT scan and image the human genome in their tumor," said Michael Kuo, an assistant professor of interventional radiology at the University of California at San Diego.

For example, the scientists could determine whether the gene that spurs the growth of blood vessels, called VEGF, was turned on or off, by statistically analyzing a CT image. Experimental treatments such as vaccines and gene therapies attack tumors by shutting down this gene's ability to feed cancer tumors with new blood vessels.

Instead of taking an invasive biopsy that could put sick patients at risk, a noninvasive CT scan could determine the activity of VEGF and many other genes.

The findings, in the May 21 online edition of the journal Nature Biotechnology, show scientists have associated more than 5,000 genes with CT imaging traits.

In the other research, scientists have developed a compact, precision-magnetic microscope based on a new state of matter. The technology, the researchers said, is as effective as current imaging devices such as MEGs for the brain and MCGs for the heart, which require a hospital visit because the devices are large and expensive.

It's made possible by a state of matter discovered just 12 years ago called the Bose-Einstein condensate.

Physicists at UC Berkeley have developed the device by harnessing a special property of Bose-Einstein condensates: Because they are cooled close to absolute zero, they are as free of vibrations and thermal noise as a quantum system can be, and are thus like a quiet, acoustically pristine concert hall. Tiny magnetic fields that might be unobservable in other systems are easily picked up.

Dan Stamper-Kurn, assistant professor of physics at Berkeley, and his colleagues published the work in the May 18 issue of Physical Review Letters. Unlike the superconductors that power current magnetic imaging, Stamper-Kurn's device is cooled not by gigantic refrigerators but by lasers – making the prospect for miniaturization bright.

"I don't know when will come the day that you can strap a Bose-Einstein condensation experiment to your head," Stamper-Kurn said. But, he added, both the lasers and the vacuum chambers needed to make a condensate are shrinking fast.

Dmitry Budker, a physicist at Berkeley (not a co-author of the paper), believes the work could lead to a high-powered magnetic microscope, studying computer chips or individual cells and neurons.

"As with all new technologies," Budker said in an e-mail, "unexpected vistas might open."

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