Which hypothesis assumes that a dose–effect relationship derived from high-dose-rate data can be extrapolated to lower doses and to zero?

• A. Quadratic Hypothesis
• B. Threshold Hypothesis
• C. LINEAR Hypothesis
• D. Exponential Hypothesis

Answer: (C)

A straight-line dose–response means the effect is directly proportional to the dose with no dose at which effects begin. This allows predictions from high-dose-rate data to apply to lower doses and to zero because halving the dose halves the effect, and zero dose yields zero effect. In radiation risk terms, this is the linear no-threshold idea: any amount of exposure carries some risk, and risk scales linearly with dose. Other models introduce a threshold or curvature, which would break straightforward extrapolation to zero from high-dose data, so they don’t fit this assumption as well.