Radiation hormesis: an ecological and energetic perspective

Does low dose internal radiation increase lifespan?

No significant differences in lifespan could be established between control dogs and dogs given 241Am, 228Th, 90Sr, 228Ra, 226Ra or monomeric 239Pu at low dosage levels that induced less than 10% skeletal malignancies (low dose animals) in the Utah beagle colony when all dogs surviving at least 1 y were included in the analysis and dogs given individual radionuclides were considered separately or together. Censoring or exclusion of dogs from these groups that were diagnosed with skeletal malignancies or that died in a gran mal epileptic seizure made no important difference to these results. Therefore, an enhanced lifespan of low dose dogs as compared with controls could not be established. It is concluded that low doses from internal (mainly skeletal) deposits of these radionuclides probably do not benefit the survival of individuals so exposed.

Are the biopositive effects of X-rays the only benefits of repetitive mammograms?

Breast cancer mortality rates fell between 1990 and 2000. When something positive occurs in medicine attempts are usually made to explain the observation or claim the credit. In this case, credit has been given to improvements in standard treatments and to increased use of mammography, each said to have made a contribution. Published data on the results of clinical trials utilising high-dose radiation or chemotherapy do not support this position. Improvements in breast cancer mortality are more likely to be the result of the biopositive effects of the low-dose radiation delivered during mammography, based on lower death rates from breast cancer in women subjected to repetitive mammographic screening, albeit with no significant change in all-cause death rates. This is supported by a study in which breast cancer rates were lowered by diagnostic X-rays of the chest.