Most of the body's protective mechanisms reach their maximum effect at a radiation dose of about 0.1 Gray (possibly earlier, see attached curve piece). This dose is approximately twenty times the average background radiation that is always present. After that, the effect drops off. An exception is the suicide of degenerate cells. It increases continuously with increasing radiation dose (dashed curve). Image: Ludwig Feinendegen / Atoms for Peace, Interscience
Read aloud: There is no doubt that radioactive radiation in carcinogenic medium and high doses. However, there is no convincing scientific evidence for the often repeated by some politicians and even experts mantra allegation that there is no lower limit for the development of cancer, so even the least amount of radiation could - with a correspondingly low probability - produce cancer. On the contrary, recent experiments and statistical evaluations suggest that living things respond to low levels of radiation as well as, for example, the penetration of viruses or bacteria into the body: they increase the body's own protective mechanisms and result in a period of several hours to several months the stimulation by the small radiation dose better protected from cancer than before. "The current radiation protection regulations are based on the assumption that the risk of cancer increases proportionally with the dose, and that even the smallest dose carries a cancer risk, " explains the nuclear physician Ludwig Feinendegen, who taught as a professor at the University of Dusseldorf before his retirement and the Institute of Medicine of Forschungszentrum Jülich. However, this proportionality assumption relies exclusively on studies on animals and humans exposed to high to medium radiation doses, such as the survivors of atomic bombing of Hiroshima and Nagasaki. The mathematical relationship determined was then simply transferred to low radiation doses in radiation protection regulations.

While there is no doubt about the validity of this relationship for medium and high doses and their harmlessness is undisputed, evidence suggests that low doses trigger protective reactions in the body that can prevent, repair or even eliminate DNA damage. The DNA is the carrier of the genetic material and is at the core of every body cell.

According to current knowledge, cancer is caused by several consecutive, non-repaired or incorrectly repaired DNA cell damage. "Recent experimental data show that toxic substances that are produced continuously in human metabolism cause serious DNA damage every day in every tenth body cell, " says Feinendegen. Assuming that a human body has about 20 to 40 trillion cells, causing several trillion serious DNA damage each day, "this immense number raises the question of why cancer develops in an intact organism - in relation to a cell - is such a rare event, "adds Feinendegen. The emergence of a single cancer cell can trigger cancer in a human being.

Many scientific studies from the past two decades point the way to an answer. For example, a statistical study of workers in the nuclear power industry who were constantly exposed to low levels of radioactive radiation revealed a significantly reduced risk of cancer. This applies to radiation doses that do not exceed 20 times the average background radiation. Workers exposed to more than 40 times natural background radiation for longer periods of time increased the risk of cancer. The omnipresent background radiation is exposed to every human being. It comes partly from space and partly from the decay of the radioactive noble gas radon, which constantly rises from the earth's interior. display

The studies show that low doses of radiation stimulate several defense mechanisms in the body, which act sequentially. The first level of defense provides for the breakdown of reactive oxygen-bearing chemical compounds. These are produced not only by the normal metabolism, but also by radioactive as well as by X-rays. It is these chemical compounds that eventually cause most of the serious DNA damage already mentioned. In case of damage that still occurs, the second level of defense begins. This is the always active DNA repair mechanism of the cells. Its activity is also stimulated by low radiation doses. However, the studies show that this stimulation decreases with age.

If this protection mechanism also fails, then the third defense stage comes into play: the damaged cell kills itself. Unlike the first two stages, this protection mechanism is also stimulated by medium and high doses. The fourth level of defense is the immune system, which can also be stimulated by low radiation doses. It detects cancer cells and destroys them. In animal experiments, the stimulation of the immune system persisted for up to several months after irradiation with low doses. However, the experiments also show that higher doses reverse the effect and weaken the immune system.

"Based on all these findings, it is currently being discussed internationally whether the proportional dose-response relationship for radiation protection should be maintained even for small doses, " says Feinendegen. "However, this has been publicly ignored by the established radiation protection bodies. Personally, I would like to introduce a dose threshold in radiation protection below which no protective activity is needed. This threshold should be worked out well in a consensus process. It must also be taken into account, among other things, that the various protective mechanisms are controlled by the genetic material and therefore have a slightly different effect on every person. "

Ludwig Feinendegen .: Damage propagation in complex biological systems following exposure to low doses of ionizing radiation, atoms For Peace: to International Journal, Volume 1, Number 4/2007, Pages: 336 - 354 Ludwig Feinendegen: Hormesis Like Does Low Radiation Work ?, Energy Facts 2005 Axel Tillemans

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