Environmental Health Perspectives • volume 120 | number 12 | December 2012 A 453 highly exposed individuals. The authors then fitted a linear ERR model to the data of the meta-analysis and derived mortality risks at low-level radiation by extrapolation. Linear extrapolation is used in radiation protection if cohort strata pertaining to low doses and dose rates have low statistical power. There ...

The effect of exogenous CaCl2 on photosystem I and II (PSI and PSII) activities, cyclic electron flow (CEF), and proton motive force of tomato leaves under low night temperature (LNT) was investigated. LNT stress decreased the net photosynthetic rate (Pn), effective quantum yield of PSII [Y(II)], and photochemical quenching (qP), whereas CaCl2 pretreatment improved Pn, Y(II), and qP under LNT s...

Both the linear (at low doses)-no-threshold (LNT) and the threshold models (S-shapes) dose-response lead to no benefit from low exposure. We propose three new models that allow and include, but do not require - unlike LNT and S-shaped models - this strong assumption. We also provide the means to calculate benefits associated with bi-phasic biological behaviors, when they occur and propose:THREE...

This note explores whether the lowest dose-rate mortality data from the beagle tissue archive might be consistent with the Linear No-Threshold (LNT) Model and might give evidence in favour of that model. I suggest that the answer may be ‘yes’; further statistical analysis will be required to establish how strongly the data favour LNT over alternative non-linear models. 1 The mortality data A pa...

Low doses in the mGy range cause a dual effect on cellular DNA. One is a relatively low probability of DNA damage per energy deposition event and increases in proportion to the dose. At background exposures this damage to DNA is orders of magnitude lower than that from endogenous sources, such as reactive oxygen species. The other effect at comparable doses is adaptive protection against DNA da...

Maurice Tubiana, MD Ludwig E. Feinendegen, MD Chichuan Yang, MD Joseph M. Kaminski, MD T he carcinogenic risk induced by low doses of ionizing radiation is controversial. It cannot be assessed with epidemiologic methods alone because at low doses the data are imprecise and often conflicting. Since the 1970s, the radiation protection community has estimated the risk of low doses by means of extr...

Radiation protection policy in the United States and in most of the world is based on the assumption that the risk of a radiation induced fatal cancer is linearly proportional to the dose. This is known as the linear, no-threshold (LNT) model of radiation risk. There are no human data to support this assumption for a short-term dose below 0.2 Gy ̄the equivalent of about two centuries of exposure...

There is a vigorous debate about whether or not there may be a "threshold" for radiation-induced adverse health effects. A linear-no threshold (LNT) model allows radiation protection practitioners to manage putative risk consistently, because different types of exposure, exposures at different times, and exposures to different organs may be summed. If we are to argue to regulators and the publi...

On June 23, 2015, the US Nuclear Regulatory Commission (NRC) issued a formal notice in the Federal Register that it would consider whether "it should amend its 'Standards for Protection Against Radiation' regulations from the linear non-threshold (LNT) model of radiation protection to the hormesis model." The present commentary supports this recommendation based on the (1) flawed and deceptive ...

The Linear No Threshold (LNT) hypothesis states that ionizing radiation risk is directly proportional to dose, without a threshold. This hypothesis, along with a number of additional derived or auxiliary concepts such as radiation and tissue type weighting factors, and dose rate reduction factors, are used to calculate radiation risk estimates for humans, and are therefore fundamental for radia...