Dr. Tsubokura's Radiation Lecture Vol.144

Author: Masaharu Tsubokura M.D., PhD.

Editors: Akihiko Ozaki M.D.,PhD., Yuki Senoo MUDr.


287. It is impossible to prove the absolute zero health impact of radiation exposure

 The genetic effects associated with radiation exposure are thought to occur in a "stochastic" manner, which means exposure to a higher dose of radiation increases the probability of adverse genetic effects.


    In other words, the relationship between the radiation dose and the risk of cancer development is proportional. Today, we understand that the higher the level of radiation exposure, the more significant the impact on health, and the lower the level of radiation exposure, the smaller the impact.


 Some of you may think that no matter how high the radiation dose is, there is always a certain risk of developing cancer in the future. However, this idea of "no matter how small the radiation dose is, the health effect is never zero" is just a theory with no scientific

evidence.


 The survivors of the atomic bombings in Hiroshima and Nagasaki were exposed to radiation of less than 100 millisieverts yet had no apparent increased incidence of cancer. Furthermore, no genetic effects have been observed in the offspring (the second generation exposed to radiation) of the survivors in Hiroshima and Nagasaki, including cancer and other diseases associated with radiation exposure.



 When organizing radiation protection measures and guidelines, it is safer to build protection plans based on the assumption that even small doses of radiation have a health effect. Moreover, in this way, it is easier to compare with other health risks, nevertheless, since there is no proof of the health impact of a small dose of radiation exposure.



288. Difficult to observe the health impacts of low-dose radiation

 The health impacts of low-dose radiation are often said to be unknown. Although it is still under investigation, a lot has been learned from experience.


    For example, previous research demonstrated that the survivors of the atomic bombing in Hiroshima and Nagasaki who received a significantly high level of radiation had an increased incidence of developing cancer. On the other hand, the survivors exposed to radiation less than 100 millisieverts had no apparent increased incidence of developing cancer.


 While these results strongly support that there were no health effects from low-dose radiation confirmed, they do not indicate that low-dose radiation has “absolutely no health impact.” Just as it is difficult to prove the non-existence of the devil, it is also difficult to completely disprove the non-existence of something that does not exist in this world.


 However, it should be noted that although we still do not know whether there are some health effects from low-dose radiation, this does not mean that we have no idea about whether low-dose radiation may cause a