JEFFREY BROWN (Newshour): Now, tracking the spread of radiation in Japan eight months after the tsunami caused a nuclear accident.
Japanese people are using new technology and the power of crowdsourcing to find hotspots.
NewsHour science correspondent Miles O'Brien has the second in a series of stories from Japan. (first: "Earthquake Prediction: Could We Ever Forecast the Next Big One?")
MILES O'BRIEN: In Japan, these days, you never know where you're going to find a hotspot. We are at a highway rest stop halfway between Tokyo and Fukushima, and we are looking for the kind of hotspot you would just as soon avoid.
PIETER FRANKEN, Safecast Japan: On the roof, the cesium didn't really stick very well, so it all flushed down and when it hit the concrete or the stone here, it bonded. So this is like a micro hotspot.