A brief article in the June 2011 issue of “Redbook Magazine” discussed radiation and when to be concerned.
“Radiation is all around us. Â When should you worry?
The nuclear crisis in Japan sparked not only debate about the safety of power plants but also fear over radiation we encounter every day. Â But Henry Royal, M.D., a nuclear medicine specialist at Mallinckrodt Institute of Radiology in St. Louis, offered this reassurance: The doses of radiation that traveled from Japan and our daily exposures are too small to pose much risk. Â Radiation is a weak carcinogen, so only much larger amounts harm your health, he says. Â Experts discourage unnecessary exposure, but this factoid puts the danger in context: To hit the upper yearly exposure limit for nuclear power plant workers, a person would have to get a heart CT scan, 10 mammograms, about 252 chest X-rays, and spend about 100 hours in an airplane…[here’s] how much radiation you get from common sources.
Acute radiation sickness begins: 100,000 millirems (mrems)
Annual recommended limit for nuclear power plant workers: 5,000 mrem
Getting a cariac CT scan: 2,000 mrem
Getting a whole-body CT scan: 1,000 mrem
Living at high altitude (radiation from the atmosphere): 52 mrem/year
Getting a mammogram: 42 mrem
Smoking a pack of cigarettes: 36 mrem
Living at sea level (normal radiation from the atmosphere): 26 mrem/year
Having a chest X-ray taken: 10 mrem
Traveling in an airplane: 0.5 mrem/hour
Having a dental X-ray taken: 0.5 mrem”