The pdf of the latest readings of radiation in the areas surrounding the Fukushima Daiichi Nuclear Power Plant (marked with an X on the map inset) may be viewed here.
Namie Town remains the hardest hit with one startling sampling point as high as 21.1 microsieverts/hour, which totals to about 185 millisieverts/year. Normal there is 1 millisievert/year.
Americans typically get about 6 millisieverts/year from all sources environmental, travel- and medical-related. In a long lifetime of 80 years one wouldn't accumulate 500 millisieverts, but in Namie you could have theoretically already come close to that if you had stayed there for the two years since the accident because the levels were much higher in the immediate aftermath.