Quite linear chromosomal aberrations in a sperm cell of Drosophila were shown by experiment. Madam Curie may have died by leukemia caused by radiation. Many uranium miners died from lung cancer. Radium dial painters died by bone tumor. Many X-ray technicians died from leukemia. Furthermore, clear hazard due to leukemia and cancer was shown by the epidemiological survey of Hiroshima and Nagasaki survivors.

However, not only the scientific achievement of recent 20 years in the field of molecular biology and nuclear medicine but also the confirmation of the radiation hormesis brought us much information on the damage control activities in our body such as DNA repair, cell apoptosis, and adaptive response. These scientific data gave us a clear evidence of the fundamental difference on the health effects between the instantaneous high dose radiation and long term irradiation of low dose rate radiation.

In parallel with these, many scientific data such as the following were obtained:

The clear threshold of 10 Gy shown in radium dial painter epidemiology; no risk increase of lung cancer under 25 WLM by 2 WL radon shown by thousands of rats tested in France; and radiation adaptive response shown by many animal tests in Japan; etc.

These sources of scientific knowledge produced a necessity to reconsider the radiation paradigm from the scientific stand point.

On the low dose rate of radiation especially, the epidemiological research performed by Prof. Bernard Cohen of the University of Pittsburgh on the relation of lung cancer and indoor radon concentration covering all of the United States showed clearly negative correlation, different from the concept being given by EPA and ICRP. The same result was reported from Germany by Prof. Klaus Becker, and by others.

The problem of the leukemia of X-ray technicians could not provide good scientific data, because the dose of each person exposed was not quantitatively known.

Prof. Emeritus Sohei Kondo published a book called "Health Effects of Low-level Radiation" in 1993. This became famous world widely because clear insights and judgments were shown on rather unclear points of radiation and cancer. He explained the up-to-date state of science telling the multi-stage progress of cancer passing through inherent damage control mechanisms such as DNA repair and cell apoptosis, completely different from the conventional target theory.

Under this situation, repeated emphasis of the linear theory of the radiation hazard was given by the people of RERF and ICRP based only on the data of the survivors of Hiroshima and Nagasaki. This produced a peculiar feeling in the audience in the Radiation Symposium of IAEA/WHO 1997 in Seville. It was quite natural under the present scientific knowledge that oppositions raised there were not only many questions and opinions but also strong assertions of reverse concepts explaining: "How erroneous the non-threshold theory is." by Prof. Emeritus T.D. Luckey of the Univ. of Missouri and Prof. Emeritus Myron Pollycove of the Univ. of California and the US NRC, supported by many presentations in the poster session.

As a conclusive remark in the final day of the symposium, one of the key persons representing RERF in Hiroshima gave a historical and scientifically great judgment that acute doses of radiation with atomic flash at Hiroshima and Nagasaki do not provide the information on the health effects by chronic doses. He was on the scientifically right position to give the valuable data showing how the atomic bomb is formidable by the treatment of the data on Hiroshima and Nagasaki , but high dose in one second has nothing to do with the discussion on the health effects of long term exposure by low dose rate radiation. He pointed that we have to positively proceed on the research on the health effects of low dose rate of radiation.

On this issue, US DOE prepared in the last September a budget of $ 3M for 1999 to begin the research on the health effects of low dose rate radiation putting emphasis of clarification of the detail mechanism of the efect in the extent of molecular biology. A new organization named International Center on the Low Dose Radiation Research was formulated last year at the University of Ottawa.

However, the key event which triggered such an innovational movement toward the paradigm charge has to be envisaged.

T. D. Luckey, Prof. Emeritus of the University of Missouri published a big paper with 200 references in the Journal of Health Physics in December of 1982. The assertion he made with the enormous number of the data was "Radiation Hormesis" explaining various bio-positive effects of low dose rate radiation. He published two books on this issue and concluded clearly in the last chapter of his second book as follows with figure.

1. The radiation deficient atmosphere which is unhealthy is to be estimated as such as one hundredth of natural radiation background.

2. The optimum radiation level for your better health and vitality is one hundred times of natural radiation background.

3. The acceptable level of chronic radiation is one thousand times of natural radiation background taking the safety factor of ten, conservatively.

These were extremely different from what we learned in school and opposite of common sense. If these were to be true, we had been suppressing the peaceful use of nuclear energy by formidable misunderstanding world widely, and had brought on the serious extent of air pollution and global environmental problems due to fossil fuel burning.

It is ten years since CRIEPI started the research of the verification study on the "radiation hormesis" to find the scientific truth.

For the first step, many interesting papers such as an originally new epidemiological study of Hiroshima/Nagasaki survivors reported by the University of Nagasaki, another study of radon villagers about cancer therapy, impressive data on the success of combined use of low dose whole body irradiation with high local dose treatment of Non-Hodgkin’s lymphoma were brought in, then various animal tests program followed.

The increase of SOD enzyme which protects cells from the attack of free radical, the enhancement of p53 gene which suppress the tumors, the adaptive response caused by low priming dose which clearly increased the survival rate after receiving extremely high challenging dose gave deep interests to many scientists in the field of biology and basic medical research. Following many suggestion and request of these scientists, CRIEPI had to expand the research on the radiation hormesis to cooperate with 14 universities and research institutes. The University of Innsbruck, Austria, which had been working on successful radon therapy, such as at Bad Gastein, Austria, found strong interest in the data of these animal tests. They invited us to have a presentation in a pre-conference of European health forum on the radon therapy symposium.

Our animal test data showed not only adaptive response due to the enhancement of DNA repair and cell apoptosis, but also protective response to diabetes and hyper-tension and hormone increase leading pain relief, stress moderation, and vitalization, etc.

In November of 1994, the presentation of the CRIEPI on many research data about radiation hormesis gave an impact to US bio-medical specialists, at the special session of the Winter Meeting of American Nuclear Society in Washington D.C.

Mr. James Muckerheide , the chairman of the session and additional sessions in 1995 at ANS established a foundation named Radiation, Science, and Health (with many medical leading specialists the next year, in 1996. The chairman of the scientific advisory board of the foundation is Prof. Emeritus Myron Pollycove of the University of California, now a medical advisor of USNRC. He is also a leading person in the society of nuclear medicine. The purpose of the foundation is to explain to the people about the scientific evidences that clearly show the hypothesis of Linear Non-Threshold hazard of radiation is completely erroneous, and DNA damages caused by free radicals etc. under daily life are far higher than the damages caused by low dose rate radiation, and both of those damages are being over come by fundamental damage control system such as DNA repairs and cell apoptosis. This foundation suggested IAEA to hold an international symposium of Low Dose Radiation.

On the behavior of low level radiation such as natural background radiation in our body, a distinguished scientist, Pro. Dr. Ludwig Feinendegen has performed very analytical research for more than 30 years in Germany and is now continuing the work in the United States ater retirement as the President of Julich Research Institute. He could not attend and speak in this symposium because he is the key person of the specialist work shop beginning rom April 26th in NIH (the world’s largest medical research center in U.S.), on the eatures and scope of the several years research or the new paradigm of the health ects of low level radiation which DOE decided to start rom this year.