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By Amanda Gardner

FRIDAY, March 25, 2011 (Health.com) — A few days after radiation started escaping from the crippled nuclear reactors in northeast Japan, internist Peter Galier, MD, began fielding calls from nervous patients some 5,000 miles away from the disaster.

"Media reports are talking about how these radiation plumes are drifting across the ocean to the U.S. and levels of radiation are being detected," says Dr. Galier, who is based at Santa Monica–UCLA Medical Center, just outside Los Angeles. "A lot of people are very concerned."

The eight other doctors in Dr. Galier's practice have received similar calls—and they're far from the only ones. Radiation fears, like the radiation plumes themselves, seem to dissipate as one heads east, but doctors all over the U.S. are reporting inquiries from anxious patients who are wondering how bad the radiation will get, whether they should stay inside, and if there is anything they can do to protect themselves.

Doctors and health officials unanimously agree that these fears are unfounded. Although trace amounts of radiation have indeed reached U.S. shores, experts have repeatedly stressed that these levels of radiation pose no health threat—especially when compared to the threat in the vicinity of the damaged reactors, where residents are being urged to take precautions.

All the same, some people in the U.S. want to be reassured. And their first question seems to be whether it's advisable to take potassium iodide pills to prevent radiation poisoning.

Earlier this week, Arch Carson, MD, an associate professor of occupational health at the University of Texas School of Public Health, in Houston, received a call from a young man who had managed to obtain some potassium iodide tablets—drugstores around the country have been selling out—and wanted clarification about the side effects mentioned on the label.

"Based on everything we know about that disaster, there's no reason for anyone in this country to take prophylactic action," Dr. Carson says. "The emissions are likely to be so diluted or insignificant when they get to this part of the world that it won't matter. You would only use it if you were within a certain radius of a high concentration of radioactive iodine."

Dr. Carson also points out that potassium iodide protects only against thyroid cancer, not other potential radiation-related ills such as lymphoma or skin burns.

Herbert Chen, MD, the chief of endocrine surgery at the University of Wisconsin School of Medicine and Public Health, in Madison, has received two office visits from concerned patients. One was a thirtysomething woman who had been treated successfully for thyroid cancer two years earlier and wanted to know if the drifting radiation was likely to put her at greater risk for a recurrence.

He told her no. "The risk of thyroid cancer [from radiation] is negligible in adults," Dr. Chen explains. "The risk is predominantly in children and doesn't happen for 20 years. Also, the cancer is generally very well treated and not life-threatening."

Next page: Anxiety spreading east

Though the anxiety regarding radiation seems to be more pronounced on the West Coast, doctors as far east as New York and Miami say they have received calls as well, in some cases from people who are concerned about relatives out west.

Robert Schwartz, MD, the chairman of family medicine at the University of Miami Miller School of Medicine, even got a call from a concerned Californian couple with young children, who inquired about potassium iodide supplies in Florida.

"I told them the risk was absolutely minimal, and that it wasn't necessarily a good thing to do, and that they should wait until the health department makes a statement and tells people to actually take the pills," Dr. Schwartz says.

Likewise, Dr. Carlson has been reassuring callers that federal agencies are closely monitoring radiation levels and screening products imported from Japan. "At this point," he says, "we don't need to protect ourselves."

The risks are, of course, much greater in Japan, where radiation has infiltrated the drinking water and food supply. But hopefully time and distance will ease concerns there, as well.

Dr. Chen has scheduled a trip to Japan in August, to attend a gathering of the International Association of Endocrine Surgeons where, ironically enough, a main topic of discussion will be thyroid cancer.

"My wife doesn't want me to go. She's worried about me eating and drinking there," says Dr. Chen, who fully expects to make the trip. "I told her not to worry."