According to LNT, any and all radiation doses, even background and below, are harmful and linear with dose.

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The straight-line portion of these types of curves above Earth background has been the basis for the Linear No-Threshold Dose hypothesis, or LNT.

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Dr. GERBER: It's approximately four times the natural radiation dose that we all receive annually in the Unites States, as a result from background radiation due to radon and other materials.

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