Whereas the carcinogenic nature of high dose radiation is well established, the health effects of low dose radiation are still being debated.  The current radiation safety paradigm is based on the linear no-threshold (LNT) premise that even the smallest amount of radiation may cause DNA damage and mutations increasing the risk of cancer.  Though mutations are essential in the carcinogenic process, mutations do not necessarily result in clinical cancer.   Autopsy studies have shown that the presence of cancer cells is not a decisive factor in the occurrence of clinical cancer.  On the other hand, suppression of immune system more than doubles the cancer risk in organ transplant patients, indicating its key role in keeping occult cancers in check.  LNT model pays exclusive attention to DNA damage, which is not a decisive factor, and completely ignores immune system response, which is an important factor, and so is not scientifically justifiable.

The biological effects of low dose radiation are similar to that of moderate exercise in that they both lead to slightly increased production of free radicals stimulating the body’s defensive mechanisms such as increased antioxidant capacity and the immune system.  Thus, low dose radiation may be expected to reduce rather than increase cancers, since the immune system plays an extremely important role in preventing cancers.  This has been observed in many controlled animal studies.  The increased antioxidants may also help to reduce aging-related diseases since oxidative damage has been implicated in many of these diseases.  External administration of antioxidants has failed to reduce diseases in clinical trials, possibly because there may not have been sufficient bioavailability of the antioxidants in the relevant organs to reduce the oxidative damage.  Administration of large doses of antioxidants can interfere with important cellular signaling mechanisms, resulting in worsening of health and so is not recommended.  Thus we are at an impasse in dealing with the underlying cause of aging-related diseases.  Low dose radiation may provide a solution to this impasse by endogenous production of antioxidants in the relevant organs.  Controlled animal studies have shown reduction of many of these diseases using low dose radiation, and some human studies have also shown promising results.  Low dose radiation can be used to supplement traditional treatments which address the symptoms of the diseases, in order to reduce the recurrence of the diseases.  The increased antioxidants from low dose radiation may also reduce the adverse side effects of cancer therapies, since many of these are caused by oxidative damage also.  Another potential application of low dose radiation may be in providing the benefits of exercise to the infirm that are unable to exercise.  However, study of these potential beneficial effects is not presently feasible because of the LNT model based radiation safety regulations and the resulting fear of low dose radiation among the public.  A paradigm shift in radiation safety is warranted to enable the study of potential beneficial effects of low dose radiation.