About half of children who go to the ER with head injuries get this radiation-heavy scan, and clinical observation first could help some who don't really need a CT avoid it.

NPR: Doc Groups Issue List Of Overused Tests, Therapies

In the most serious known injuries due to radiation at Fukushima, three workers who suffered radiation burns inside the turbine building beside Reactor No. 3, are now reported to have been standing in water that tested 3.9 becquerels of radioactivity per cubic centimeter a figure that is 10, 000 times higher that what is normally found inside a functioning nuclear power vessel.

FORBES: Japan's Government Expands Danger Zone; Unit 3 Breach 'Likely'

There were no injuries and little release of radiation from that incident, which remains the worst commercial nuclear accident in U.S. history.

CNN: Pump triggers Three Mile Island reactor shutdown, NRC says