Energy Probe

Metabolic and energetic efficiency, and hence fitness of organisms to survive, should be maximal in their habitats. This tenet of evolutionary biology invalidates the linear-nothreshold (LNT) model for the risk consequences of environmental agents. Hormesis in response to selection for maximum metabolic and energetic efficiency, or minimum metabolic imbalance, to adapt to a stressed world dominated by oxidative stress should therefore be universal. Radiation hormetic zones extending substantially beyond common background levels, can be explained by metabolic interactions among multiple abiotic stresses. Demographic and experimental data are mainly in accord with this expectation. Therefore, non-linearity becomes the primary model for assessing risks from low-dose ionizing radiation. This is the evolutionary imperative upon which risk assessment for radiation should be based.

The International Commission for Radiological Protection (ICRP) adopted the linear nonthreshold model of radiation risk to simplify the administration of radiation protection. (ICRP 1977) At that time there were already several good epidemiological studies that contradicted the assumption. It had been known since 1973 (Frigerio, et. al.) that the 7 western U.S. states with the highest background radiation have cancer death rates 15% lower than the average for the 48 contiguous states (P<10-5). 

Information from the unpublished 1991 Final Report of the Nuclear Shipyard Worker Study (NSWS). The NSWS is the world’s largest and most thorough study of health effects of low-dose- rate ionising radiation to nuclear workers.

In accordance with current knowledge of radiation health risks, the Health Physics Society
recommends against quantitative estimation of health risks below an individual dose of 5 rem1 in
one year or a lifetime dose of 10 rem above that received from natural sources. Doses from
natural background radiation in the United States average about 0.3 rem per year. A dose of 5
rem will be accumulated in the first 17 years of life and about 25 rem in a lifetime of 80 years.

The prevailing view of regulatory agencies and advisory groups is that all radiation is bad for health, and exposure to any form of it should be minimized. While high-dose radiation, regardless of source or intention, is harmful to health, evidence is presented that chronic doses up to 100 times those of normal ambient (including medical) exposures are beneficial, mainly due to lower cancer rates. Further evidence is presented that single, acute doses of up to 50 rad are beneficial, including in treatment of cancer and gangrene. Data are cited to show that below-ambient radiation levels are unhealthful, and that some radiation may be essential for many life-forms.

The 100-year study of British radiologists is perhaps the most important article about the health effects of radiation on humans ever published. The continuity of follow-up in the study is the longest for any study of exposure to chronic radiation.

People in some areas of Ramsar, a city in northern Iran, receive an annual radiation absorbed dose from background radiation that is up to 260 mSv y_1, substantially higher than the 20 mSv y_1 that is permitted for radiation workers. Inhabitants of Ramsar have lived for many generations in these high background areas. Cytogenetic studies show no significant differences between people in the high background compared to people in normal background areas.

Discussions of possible stimulatory effects of low levels of ionizing radiation have recently become entangled with the separate but related question of whether a threshold dose level exists on the radiotoxicologic dose-response curve. This review summarizes some of the relevant historical and scientific data bearing on the question of radiation hormesis.