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Dr. Tsubokura's Radiation Lecture Vol.41

Author: Masaharu Tsubokura

Editors: Akihiko Ozaki M.D., Yuki Senoo

81. Risk factors of cancer could be something other than radiation exposure

Development of cancer induced by radiation exposure is considered to occur, irrespective of the “threshold limit value,” to protect us from radiation exposure. In other words, cancer develops in proportion to the total dose of radiation exposure received. This effect of radiation exposure is called a “stochastic effect,” as the radiation exposure elevates the stochasticity or possibility of cancer.

This concept is very different from that for nosebleeds or bleeding: These symptoms only appear following an extremely high level of radiation exposure.

The fact that radiation exposure increases the risk of developing cancer does not mean that you will develop cancer in the future after being exposed to a low level of radiation, nor that you will not develop cancer as long as you avoid radiation exposure. Indeed, a variety of risk factors, such as lifestyle and infectious diseases, are potential reasons for cancer.

Thus, you may wonder how much radiation exposure would increase the risk of cancer in each individual. This has been calculated primarily based on the result of an investigation conducted in the Hiroshima and Nagasaki prefectures after World War 2.

82. DNA Damage Can Be Restored

Inside all the approximately 60 trillion cells that construct our body, various substances are produced and broken down every day. Although we need various essential substances, no one would spoon to you. Thus, our body has to produce the substances required based on the blueprint equipped in each cell.

The original copy of this blueprint is what is called DNA. When we need specific substances in our cells, only the part of the DNA (original copy) that accounts for the specific structure is copied, and the target substances are produced based on this copied blueprint.

Because DNA is the original blueprint, we have to prevent it from being destroyed or getting chipped at all costs.

For its safety, two original copies are essentially saved in our cells. Therefore, even when radiation or other things destroy the original blueprint (DNA), some functions are able to repair the damage by comparing with the original copy.


The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, on July 24th and 31th 2016 was reproduced for MRIC Global under the author's permission.

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