The large, black SUV passed the woman on the left, abruptly slowed down, and then dropped behind her. Suddenly, flashing red and blue lights lit up her rearview mirror.
"Ma'am, you were pulled over because you set off a nuclear radioactive alarm," a man dressed in a blue jumpsuit-type uniform and a baseball cap said in a monotone.
It sounds like a scene from the movie "Men in Black." A select group of state troopers and inspectors from the state Department of Motor Vehicles now wear ultra-sensitive, portable radiation detectors on their belts to check for dangerous materials inside large trucks.
But the 45-year-old Suffield woman wasn't hauling nuclear waste. She had been injected with a radioactive substance for a common medical test.
Relieved to have completed a series of stress tests on her heart on Feb. 23, the woman was heading home, seatbelt on, and cruising at the 65 mph speed limit on I-91 north.
Inspectors in the SUV were on a routine assignment when the device started beeping and they homed in on the woman's car.
The woman, who asked not to be identified, wasn't angry about being stopped, nor particularly inconvenienced, but baffled as to how police detected radiation from a substance injected into her body hours earlier.
The pager-size devices are so new to Connecticut law enforcement that even state homeland security officials and top state police were at first perplexed by the woman's story.
"I've never heard of this being done in my entire life," James Thomas, commissioner of the state Office of Emergency Management and Homeland Security, said Wednesday. On Thursday, he called Public Safety Commissioner Leonard C. Boyle, who also did not know that radiation could be detected in a moving vehicle.
"I was surprised and did not expect that these devices could detect radiological activity in a moving car," Boyle said. Both men said they knew that radiation testing is regularly done at truck stops.
Edward Wilds, director for the division of radiation at the state Department of Environmental Protection, solved the mystery.
Wilds said Thursday that he was consulted on the purchase of the device. He said DEP workers have carried them for a while to detect radiation at scenes involving biological hazards. The state purchased 50 of the "radiological pagers," dividing them between the state police and the DMV, said Bill Seymour, a DMV spokesman.
Seymour confirmed Thursday that a motor vehicle inspector pulled over the woman.
"When these things go off, they have an obligation to check it out," he said.
Seymour said the inspector, who has full police powers, identified himself as being from the DMV and that his truck was marked with the agency's insignia.
"These are very sensitive devices," Seymour said, adding that some officers have reported them going off in buildings "because someone in the next room on the other side of the wall had a stress test."
Doctors said they have heard of radiation sensors going off at nuclear plants after patients have had stress tests, but not along highways.
"It is certainly conceivable," said Dr. Bernard Clark, chairman of the department of medicine and associate chief of cardiology at St. Francis Hospital and Medical Center in Hartford. "The glass and steel of a car wouldn't stop it, if they have an extremely sensitive indicator or detector."
In stress tests, which monitor a patient's heart at rest and during activity, technetium and Cardiolite are injected. Cardiolite is a substance that helps move technetium, a radioactive isotope, to the heart muscle, allowing doctors to look at how the blood flows to it, Clark said. The substance has a half-life of about six hours, and then starts to dissipate, he said.
"These are very safe agents," he said, adding that they are also used to scan other organs.
The woman said she quickly explained to the officer that she had just undergone a medical procedure that involved a radioactive substance. She had to sign a bunch of forms that explained the risks.
The officer seemed satisfied by her answer, and said, " `That's usually what it is,' " she said. He asked for her license and registration, and returned to her car a short time later.
"Nobody at my doctor's office warned me this could happen," the woman said she told the officer. "He said, `That's because they don't know.' "
She drove home and called her husband, who works for the state, telling him her strange story. Although she is glad someone is monitoring radioactivity in the state, the woman said she feels a little violated.
"I was pulled over because of something in my bloodstream," she said. "There are [federal privacy laws], and I pretty much had to tell him I had a medical test. I was going to say, `none of your business why I'm radioactive.' But that wouldn't have gotten me that far."
Clark said he assumes there will be a higher level of vigilance for radioactive material in the aftermath of the Sept. 11 terrorist attacks.
"You figure on the interstate highways people are going to ship things that shouldn't be shipped," the doctor said. "Most people aren't radioactive. If they are, you'd probably want to know why. Are you carrying weapons grade plutonium, or did you just get a stress test?"