Three Principles of Radiation Exposure
In essence, the less time spent at the source of radiation, the greater distance from the source, and using something to shield us against the source of radiation is ideal. For example, think of the sun. The sun emits ultraviolet radiation. How it affects you depends on how long you are exposed to the sun, how far away you are, and protection (such as sunscreen) used.
It’s important to note that what is being measured in Japan is not what we here in Alaska are exposed to. The farther away from a source, the less exposure there is.