Genetic Test Could Help Detect Dirty Bomb Exposure

(Jan. 21) -- The potential for deadly nuclear attacks has remained a national preoccupation since Sept. 11, 2001, and this week medical countermeasures against dirty bombs and nuclear weapons got a big shot in the arm: $43 million that will be used by Duke University specialists to create a genome-based test for detecting whether a person has been exposed to nuclear radiation.

The award was given out by the Biomedical Advanced Research and Development Authority (BARDA), a branch of the U.S. Department of Health and Human Services. It's all part of Project BioShield, a BARDA-run research program launched in 2004 by President George W. Bush to develop countermeasures against chemical, biological, radiological and nuclear agents.

If a nuclear attack occurred, thousands of survivors would be exposed to potentially harmful radioactive material. Researchers at Duke, led by associate professor of medicine Dr. John Chute, hope to create a portable, 30-minute test that would use blood samples to quickly screen potential victims. Chute said the test would do what the human eye cannot.

"Two people will look similar, whether they've been exposed to dangerous amounts of radiation or not," he said. "Triage for a nuclear attack would be next to impossible without this kind of test."

A portable genetic radiation test sounds sci-fi, but Chute and company are already well on their way. In 2007, the team identified 25 human genes that respond to radiation. By testing for that characteristic pattern of changes, they can make a correct diagnosis in 90 percent of cases.

Those preliminary discoveries were funded by the National Institutes of Allergy and Infectious Diseases. Now, BARDA is shelling out more money for the Duke team to validate the findings on human patients and then work with collaborators at a California biotech firm and the University of Arizona to design a portable testing instrument. The system would quickly screen blood samples for those 25 genetic markers and determine which civilians needed treatment.

Every cell in the body is affected by radioactive exposure, but Chute says fatalities are usually caused by blood and immune system failure. "Those cells proliferate very quickly, so in a matter of days you'd see fatigue, anemia and infections," he said.

Of course, Duke's diagnostic tool wouldn't prevent fatalities: The Department of Homeland Security estimates that a 10-kiloton nuclear weapon would be lethal within a half-mile. But outside that zone, those exposed to radiation could survive if diagnosed and treated quickly. Chute anticipates that a triage circle surrounding a blast zone could screen "tens of thousands" within 24 hours.

Ironically, the genetic diagnostic device might be ready before the Pentagon comes up with a more accurate way to spot nuclear threats in the first place. The Duke team hopes to debut a prototype in 2015. Meanwhile, a report released last June determined that the government's "next-generation radiation detectors" -- which cost $800,000 apiece -- were only a marginal improvement over older models, which trip up on kitty litter and bananas, among other non-threats.