'Hot' humans are cause for alarm

In placing radiation detectors in key cities, ports and border crossings, defense scientists and the federal government are finding remarkable amounts of radioactive material moving around the country.

Cat litter, granite and truckloads of porcelain toilets headed for Home Depot and Lowes are setting off radiation alarms. And they're not remotely as "hot" as the humans.

With the explosion of nuclear medicine, physicians are giving radioactive drugs to people an estimated 20 million times a year. For a few days to several weeks those people are emitting gamma rays, beta particles or X-rays that can radiate beyond the walls of cars, buses and subway trains to reach the attention of anti-terror authorities.

"If you have a radiomedical treatment, you

are the hottest thing around," said Linda Groves, an ex-Navy captain who analyzes radiation-detection data for Sandia National Laboratories in Livermore.

In the event of an alarm, authorities are pulling over and questioning motorists whose vehicles come up radioactive.

"I did some deployments, and we scared some little old ladies to death," Groves said. "Doctors are not doing a good enough job of telling folks what they're carrying."

As agencies of the U.S. Department of Homeland Security look for smuggling of ingredients for nuclear and "dirty" bombs, authorities in many places are having to stop roughly one in every 1,000 vehicles and cargo shipments for closer inspection and questioning.

Most alarms are for cargo -- everything from nuclear-reactor fuel to Fiestaware saucers to small cesium sources trucked around to construction sites to test the integrity of welds. But depending on proximity to big cities and major hospitals, as many as one-third of radiation alarms in public places and thoroughfares are being triggered by medical patients.

"Even if it's 10 percent, that means on any given day, just people driving on the highways, one out of every 10,000 are running around radioactive," said Page Stoutland, head of nuclear and radiological countermeasures at Lawrence Livermore National Laboratory.

At one New York port, as many as one in

1,000 truck drivers are turning up radioactive, which indirectly suggests they're getting good preventive health care. Increasingly, truckers, police and other workers in sensitive or stressful jobs are getting mandatory stress tests requiring a trace dose of a radioactive substance.

Thallium 201 illuminates blood flow in the heart and is the most common radiopharmaceutical. It also sets off radiation alarms for up to 30 days, according to a recent study by Lionel Zuckier, a radiology professor at the New Jersey Medical School and director of nuclear medicine at University Hospital in Newark. Another radioactive drug used in thyroid treatments, iodine-131, can last up to 95 days. That's longer than doctors thought, based on their own detection devices, Zuckier said.

That's because U.S. Customs, Border Patrol and Transportation Security Administration officials are carrying radiation detectors that can be 1,000 times more sensitive than nuclear-medicine cameras in major hospitals, Zuckier said. Those cameras provide stunningly detailed shots of the human body in part by ignoring most of the artificial radiation.

"That's why we get an image that makes some sense. Otherwise it would be a blur," he said.

The homeland-security detectors are designed to take in as much radiation as possible and have hair-trigger alarms set just above natural background.

"These things are extremely sensitive," Zuckier said. "It's a whole new level of detection."

The startling radiation readings on Americans is just one of several insights into the human and natural world that the U.S. government is getting as it deploys new sensing devices and monitoring technologies nationwide.

Bioterrorism detectors are picking up bits of anthrax and other natural pathogens in the wind. Airport metal detectors are fingering people who have knee and hip replacements or shrapnel from old war wounds. Chemical agent detectors sometimes sniff hair sprays, cleaning agents and traces of pesticides, which share some similarity with nerve agents.

In some public places, such as subways, scientists have been dismayed at having to recalibrate their chemical or biodetectors to ignore sizable amounts of airborne grime.

These are what scientists call background, or noise. For radiation detection, it has an acronym, NORM, for naturally occurring radioactive material.

We call them nuisance sources. What we're trying to do is develop some procedures or engineered solutions so they aren't the nuisance that they are, said Sandia's Groves.

To us it's a matter of patient privacy, said NRC spokesman David McIntyre. They may not want to talk about their treatment when all of a sudden sirens start going off.

But eventually defense scientists would prefer not to bother radioactive patients at all. The problem is that homeland-security radiation detectors are mostly dumb; they can't tell what kind of radiation they're detecting or how energetic the particles or rays are. With more detailed, spectroscopic tests, radioactive humans stand out like a sore thumb, unmistakable for a nuclear weapon or a dirty bomb.