How do I explain such a phenomenon? I haven't the foggiest idea... and I don't think anyone else does either. But if there were a possibility I could add 20% - 40% to the life span of my child by exposing myself to 100 cGy of radiation, that wouldn't be much of a decision. It is questions like these that we should be setting the stage for future generations to answer. Instead we are planning how to waste some $1 trillion cleaning up "nuclear dumps" that are less radioactive than the natural soil in many parts of our world.
You're probably tiring of mousy data, and I said we'd get on to humans after a couple more reports on rodent experiments. We'll just breeze right through these and let you practice your mental conversion from cGys to rads or cSvs to mrems (they are all the same for the radiation in all these citations).
- "The effect of neutron exposure [3.2 cGy-6.3 cGy] upon the combined sexes showed low doses decreased the natural incidence of all tumors." (emphasis added) [Meweissen, D.J. and Rust, J.H. Reticuloendotheial neoplasms in C57 black mice after fast neutron irradiation at low doses. US Atomic Energy Commission Conference 740930, Oak Ridge, 1976.]
- Mice exposed to 150,000 mrem at five and twelve days following infection with "friend [sic] virus" recovered while all of the controls died within forty days. [Shen, R.N., Hornback, N.D., Lu, I., Chan, L.T., Drahms, Z., and Droxmeyer, H.E., Low dose total body irradiation; a potent antiviral agent in vivo. International Journal of Radiation Oncology and Biological Physics, 10, 185, 1989.]
- "[Studies on mice] in the dose range 0-3 Gy by two independent research groups at Oak Ridge and at Casaccio near Rome leads, for gamma radiation and X-rays, to a statistically significant decrease of the cancer rate at low doses and therefore to biphasic relationships for tumors of the reticular tissue, for several solid tumors, as well as for cancer as a whole." (emphasis in the original) [Weber, K. Biphasic dose-effect relationships in experimental studies of radiation cancer in animals. [English summary.] Strahlenbiologie und Strahlenshutz, Hannover. October 1996. IRPA, Progress in Radiation Protection.]
- "Male mice exposed to acute doses of 2 Gy for 82 successive generations showed no abnormal offspring; this acute dose is equivalent to 50 times background radiation for humans from the time of the Roman Empire to present." [Spaulding, J.F., Brooks, M., and McWilliams, P. Some effects of X irradiation in successive generations on an inbred and hybred [sic] population of mice. Genetics, 50(Suppl.), 1179, 1964. Also in Effects of ionizing radiation in reproduction, Carlson, W.D. and Gassner, R.X., eds., Pergamon Press, London, 1963.]
- "Urinary testosterone of chronically irradiated mice, 5,000 to 10,000 mrem of X-rays per day, was increased 264% above controls." (Look out, Viagra.) [Liu, S.Z. Effects of low dose ionizing radiation on defense and adaptive mechanisms. Conference on High Background Area Research, Taishan, Nov 1988; China Medical Journal, 102, 750, 1989.]
- Of the offspring of 124 male mice exposed to 276,000 mrem of X-rays and 124 control mice, 20 of 3,990 pumps from exposed males were stillborn, as compared to 45 of 3,418 control pups. [Luning, K. Studies of irradiated mouse populations. Hereditas, 46m 668, 1960.]
- In an experiment involving 3,505 autopsied mice with acute exposures of 18 cGy or more, the age-specific lymphocytic lymphoma rate was 16% of controls for 36 cGy exposures and 3% for those exposed to 18 cGy. [Meweissen, D.J., Rust, J.H., Harem, J., and Clement, M.J. Assessment of dose-response relationships in carcinogenesis following low radiation dosage. In Late effects of ionizing radiation. International Atomic Energy Agency, Vienna, 1978, 291.]
- Radio-resistance - the resistance to high levels of radiation exposure - in mice was enhanced by previous exposure to lower levels of X-rays. Survival of mice exposed to 700,000 mrem increased from 10% in the control group to 25%, 50%, and 82% for exposures to 120,000 mrem at one, two and three weeks of age, respectively. [Kochanski, W., et al. Immunologic analysis of the condition of increased resistance of organisms exposed to ionizing radiation. Medical Radiology, (Moscow) 1, 43, 1956. (Hmm, why would they have been interested in such a subject?)]
- Mice that had been exposed - from weaning through breeding - to 1 cGy/day had shorter generation times and higher birth rates that unexposed controls. (A later experiment on "deer mice" by the same researchers gave similar results.) [French, N.R. and Kaaz, H.W. The intrinsic rate of increase of irradiated Peromyscus in the laboratory. Ecology, 49, 1172, 1968.]
- "For newborn mice exposed to 180 rad at 0.07 R/day, the life span was significantly longer than it was for controls. At all dose levels the 2-month age group lived significantly longer than did the median controls." [Patterson, H. Wade, editor of the Health Physics Journal, elucidating experimental data by Spalding, J.F., Thomas, R.G., and Tiejen, G.L. in Life Span of C57 Mice as Influenced by Radiation Dose, Dose Rate and Age at Exposure, Report No. UC-48; LA-9528, Los Alamos National Laboratory, 1982.]
- "Male AKR mice were irradiated with 5 cGy three times a week or 15 cGy two times a week for 11 weeks from age 40 weeks. The incidence of thymic lymphoma was 80.6% in sham-irradiated mice [controls], 67.5% in mice irradiated with 5 cGy three times a week, and 48.6% in mice irradiated with 15 cGy twice a week." [Ishii, K. and Watanabe, M. Participation of gap-junctional cell communication on the adaptive response in human-cells induced by low-dose of X-rays. International Journal of Radiation Biology, Vol. 69, Issue 3, 1996.]