Fukushima daiichi nuclear accident and radiation exposure.

We consider that the Great East Japan Earthquake was a combined disaster involving earthquake and tsunami as well as the release of radioactive materials into the environment (Fig. 1). Something I would like you to notice here is that among various disasters, a radiation nuclear disaster cannot be seen; it cannot be felt; in fact it cannot be detected without special devices. Because of that, the fact that you cannot under­ stand what is happening even on the disaster site is a peculiarity of this kind of disaster. This is an important point.