Revision 1

Superseded · first revision · record

Title: Does risk stay linear below 10 rad
Plain: Protection rules assume that halving a small dose halves the risk, with no safe threshold. Direct evidence at such doses is thin and the assumption is contested.
Precise: Determine the shape of the dose-response relation for solid-cancer incidence below 10 rad ($1\,\mathrm{rad}=100\,\mathrm{erg}/\mathrm{g}$) of low-linear-energy-transfer radiation: linear without threshold, linear-quadratic, threshold, or non-monotonic. The answer must handle dose-measurement error, confounding and reverse causation at effect sizes of about 5 percent excess relative risk per 10 rad (ERR about 0.5 per 100 rad), falling to about 0.5 percent at 1 rad. An answer is a shape with confidence intervals excluding the alternatives.
Settled by: Pooled worker and medical cohorts with individual dosimetry of sufficient size and dose accuracy to separate linear from threshold models at the one-percent effect level.
Kind: well-posed
Answer type: classification
References: (empty)
Literature status: contested
Status note: The INWORKS nuclear-worker analysis (Richardson et al., BMJ 2023) reported solid-cancer mortality ERR of 0.52 per 100 rad, with a larger slope below 10 rad, while threshold and hormesis advocates dispute the dosimetry and confounding control.
Posed since: 1950