Appendix
This file is a summary version of the Radiation Risk and Protection Research Platform
Preparatory Committee's report (Japanese, 2016)
A plan of new network for low dose radiation research in Japan: PLANE
Abstract
In Japan, researchers, academic societies, the former Nuclear Safety Commission andothers engaging in research on radiation effects and protection have considered
constructing a research platform that would autonomously provide the capacity tocompile and assess information pertaining to radiation effects and protection, deduce
issues to be addressed and then work out solutions. Regulatory policies on radiation
protection need to be implemented rationally based upon accurate information. There isalso a renewed awareness of the importance that such a research platform has forsufficient and effective risk communication with the public about the health effects of
low-dose and low-dose rate radiation, and the need for such platform is expected tofurther increase in the future.
With the aim of constructing such research platform, National Institute of RadiologicalSciences, National Institutes for Quantum and Radiological Sciences and Technology(NIRS-QST) set up the Radiation Risk and Protection Research Platform Preparatory
Committee in 2016, and the committee summarized that results on the report about thenetwork; tentative name is Planning and Acting Network for Low Dose Radiation
Research (PLANET). The Preparatory Committee took into consideration previous
conceptions of research platforms in discussing such matters, specifically, reviewed a)
research issues to be resolved and examples of roadmaps for their resolution, b) functions
required of a research platform including considering research strategies and theprioritization of key topics, and c) the framework necessary for construction of a researchplatform.
Keywords: low dose, low dose rate, radiation risk, research network
1. IntroductionNational Institutes for Quantum and Radiological Science and Technology (QST) is a

new national corporation and mission of National Institute of Radiological Sciences(NIRS) includes medical application of radiation, radiation effects, radiation protection
and radiation emergency medicine. There are important issues for radiation effects,
especially decreasing uncertainty of risk estimation of low dose/low dose-rate radiation
exposures. Desirable approach is to establish mechanistic and numerical model based onstem cell biology and radiation biology at high dose rate, and then to underpin theselection of appropriate risk model of chronic exposures.
In order to carry out these researches steadily and continuously, it is necessary to promotecollaboration among stakeholders and establish all-Japan network among regulators,
academia and research institutes. QST-NIRS set up the Radiation Risk and Protection
Research Platform Preparatory Committee in 2016, and the committee summarized that
results on the report about the network; tentative name is Planning and Acting Network
for Low Dose Radiation Research (PLANET). The PLANET will identify priorities ofresearch needs, and propose strategies to improve quantitative estimation of low dose/low
dose-rate radiation risk. In addition, this network will propose support system forcooperation and collaboration researches among related researchers and institutes inJapan.
With a view toward establishing a platform of radiation risk and protection research(hereinafter collectively referred to as “research platform”), the preparatory committee
deliberated the functions, framework and other elements comprising such a researchplatform as well as the research issues to be given priority within the research platform.
A synopsis of these deliberations has been compiled and is presented here.
2. Necessity for a Research PlatformRisk assessments, the current foundation for radiation protection, are based uponepidemiological investigations conducted of survivors of the Hiroshima and Nagasaki
atomic bombings. With only epidemiological study results, it is difficult to quantitatively
assess risks inherent at low-dose levels of 100mGy and below because of statisticallimitations. Although substantial results have been obtained in basic research in the fieldof radiation biology to supplement epidemiological studies, these have not been sufficientenough to allow a direct link to be established with risk assessments based upon low-doseor low-dose rate radiation exposure to humans (exposures of approximately 100 mSv orless or 20 mSv/year or less). In our present age when low-dose or low-dose rate radiation

exposure has emerged as a real social issue since the accident at Tokyo Electric Power
Company’s Fukushima Daiichi Nuclear Power Station, there is an even greater need forrisk assessments that will serve as the basis for how regulations governing low-dose andlow-dose rate radiation exposure should be structured as well as the accompanying socialconsensus (Figure 1).

Animal experiments
Cellular experiments
contaiining conditions less than6mGy/hr and more than 2-week(except for TG91 animal study)

Dose (mGy), /( ), /A-bombsurvivors////

Figure 1. Current status of low dose/low dose-rate biological research
In Japan, researchers, academic societies, the former Nuclear Safety Commission andothers engaging in research on radiation effects and protection have considered
constructing a research platform that would autonomously provide the capacity tocompile and assess information pertaining to radiation effects and protection, deduce
issues to be addressed and then work out solutions. While that effort was underway, theaccident occurred at Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power
Station. Anxiety over the lack of accurate information about the effect of low-dose andlow-dose rate radiation on health as well as confusing risk communication turned into asocial issue engulfing the general public. It is an important issue that a correctunderstanding be held of the risks posed by low-dose and low-dose rate radiation
exposure, which the general public and radiation workers have a high likelihood ofexperiencing, and that this understanding be put to use in radiation protection regulations.

Therefore, it is essential that a (radiation risk and protection research platform)
framework be constructed so that information pertaining to the risks posed by low-doseand low-dose rate radiation exposure may be collected, analyzed, and such research
conducted to enhance scientific knowledge in a strategic manner to an extent greater than
before, that this knowledge be reflected in Japan’s regulations governing radiation
protection, and that a social consensus be secured on how such regulations should bestructured.
3. Research Platform Purposes
The research platform will have the following two purposes.
1) To bring relevant domestic organizations, researchers, and experts together to collectand analyze information about radiation effects, risks, and protection, which will provide
a basis for radiation regulations, to communicate these results broadly throughout Japanand the world, and to provide such information and assist the activities of the Nuclear
Regulation Authority and other relevant entities.
2) To consolidate specific research issues to quantitatively assess low-dose and low-dose
rate radiation risks, and to incorporate a top-down approach to clarifying the issues forachieving these purposes and proposing specific strategies.
4. Research Platform Functions
The research platform will have the following three functions.
1) To consolidate information available in Japan and throughout the world about radiation
risks, compile ideas about risks and protection, and publish reports to communicate theseideas.
2) Consider research issues and roadmaps to be pursued and update them.
3) Support joint research and assistance for utilization and training of human resources
as a long-term approach.
5. Synopsis of Priority Research Issues for the Research Platform
Below are five research issues to be given priority.
1) Epidemiological research on low-dose and low-dose rate radiation that is appropriately
designed for risk assessment
2) Clarification of mechanisms for assessing risks posed by low-dose and low-dose rateradiation
3) Intermediation with the purpose that data from animal experiments be used ininterpretation in epidemiological research
4) Relationship between radiation and the factors of age, sex, genetic factors and lifestyle5) Collection of data, including negative data, and database creation (archiving)
An ICRP Task Group (TG) studied key dose and dose rate effective factors (DDREF) inassessments of risks associated with low-dose and low-dose rate radiation and produced
a report recommending a DDREF value of 2 rather than 1, which was based on research
results from epidemiological and animal experiments. However, experts on livingorganisms believe that a DDREF of 2 is small and have pointed out the need for more
careful analysis as there are possible effects resulting from the validity of meta-analysis,
differences in photon energy as well as dose rate effect, age effect, and other variables.
In addition, although the problem remains of how to marshal the results of animal
experiments for humans in a convincing manner, animal experiments have merit because
the modifying effects on radiation impact, in other words radiation quality, dose rate andepigenetic items, may be controlled. If there are similarities in terms of organs anddiseases, these may also be correlated in the animal model and human being model. The
utility of applying the animal model to the human being model has been debated.
Based on the above, the Committee’s conclusion was to set as research issues thequestions of how to link animal experiments to risk estimation and incorporate suchmethodology, of which one research challenge is to use DDREF as the subject matter andpresent a new method that analyzes these from a biological perspective.
6. Consideration of Pressing Research Issues for the Research Platform
Comments were made about the usefulness of knowledge regarding living organisms
when forming epidemiological hypotheses, knowledge relating to dose rate affects
attributable to stem cells and commonalities in carcinogenesis in humans and mice
supporting the formation of such hypotheses, and finding methodologies, rather thanextrapolations, for establishing consistency with epidemiology. The importance ofmaking use of knowledge about living organisms in the formation of epidemiologicalhypotheses was confirmed.
There are close similarities between human beings and animals embryologically, and even

more similarities have been further found at the tissue level than the individual level. Inaddition, it is known that there are times corresponding to periods of development in miceand human beings that are dependent upon organs and tissue. In addition, certain cancers
in human beings have a similar type also in mice, and experiments have already begun
that are looking at age dependence and carcinogenesis as well as the chronologicalprocess leading up to carcinogenesis. Risks may correspond to such embryologicalmechanisms, and there have been proposals suggesting schemes for applying the resultsof animal analyses to human beings.
Based on the aforementioned, a decision was made to select issues for the purpose ofrationally and coherently interpreting the results of animal experiment data analyses andthe results of epidemiological studies with respect to points about which there is highregulatory interest and insufficient epidemiological knowledge, including biologicaleffects in low-dose areas, age dependency, and dose rate affects about which there issignificant epidemiological uncertainty. In other words, from the perspective of “how tolink animal experiments to risk estimation and incorporate such methodology, of which
one research challenge would be to use DDREF as the case studies analyzed from abiological perspective to present a new method,” it was decided that top priority issue
would be placed on making use of knowledge gained from animal models relating to age
dependency, dose rate affects and other variables in regulations, and taking into accountthe most recent developments in biology and to discuss, through deliberations among
different fields, the practical application (validation) of animal experiment data in orderto and to synthesize such knowledge with epidemiology.
7. Research Platform Framework
The framework for the research structure will be as described below.
1) A steering committee will be established, and an open and all-Japan framework
constructed that allows research institutions, universities, scholarly associations,
government and regulatory institutions, general public, and a variety of stakeholders
concerned with radiation effects, risks, epidemiology and protection to participate. This
framework will include not only experts in fields related to radiation but also other fields
and make it possible for interdisciplinary and multi-faceted issues to be considered.
2) Working groups will be established under the auspices of the steering committee toconsider specific issues.

3) The National Institutes for Quantum and Radiological Science and Technology’s
National Institute of Radiological Sciences will serve as the secretariat, which will be thepoint of contact for business activities relating to the research platform.
4) This cross-sectoral network should also aim to work together with internationalorganizations and cooperation both in Japan and abroad will be promoted. We arecommitted to promote research on low-dose radiation and deepen collaboration withMELODI.

Government
Regulatory authority-Information sharing, opinion transmission-Identification of issues for RP research-Priority setttiong, roadmap, rolling-Education and training-Support of NRA activities

Nuclear Regulation
Authority,etc.

ICRP, MELODI,IAEA, IDEA,UNSCEAR, etc.

Universities
Research institutes
Academic societies

PLANETInternational

Office (QST-NIRS)(NIRS)J-MELODI, etc.

General publicIndustries

NPO, etc.

Figure 2. Framework of PLANET
8. Effects of Research Platform Activities
1) Implementation of radiation regulations and policies as well as administrative policies
by regulatory and other organizations that are more rational and scientific.
2) Efficient progress in research and the creation of new knowledge about health effectsof low-dose and low-dose rate radiation.
3) Enhancing the general public’s understanding of radiation and contributing to risk
communication that is free of misunderstandings, biases, and confusion.
4) Strengthening cooperation among regulatory organizations, research institutions andthe general public in Japan, and the improvement of cooperation with regulatory agencies
and research institutions outside of Japan to facilitate efforts to address issues that areunable to be solved only by Japan.
5) Facilitation of the development of human resources in the field of radiation risk andprotection through joint research and research collaboration.
9. Conclusion
It is expected that the results gained from administration of this sort of research platform
will enable regulatory institutions and other organizations to implement regulatory
policies and administrative policies that are more rational and scientific as they will bebased upon accurate information about radiation effects and risks and the analysis of suchdata. In addition, consolidating research challenges that need to be resolved andpresenting policies for solving these issues will aid in effectively advancing research
related to health effects posed by low-dose and low-dose rate radiation as well as thecreation of new knowledge. Furthermore, the presentation and dissemination to thegeneral public of accurate and current information about radiation risks as well as
decision-making criteria will contribute to enhancing the understanding of radiation andfoster risk communication that is free of misunderstandings, biases and confusion. The
strengthening of liaisons among domestic regulatory agencies, research institutions andthe general public through the research platform activities as well as the enhancement ofliaisons with regulatory agencies and research institutions around the world will also
promote efforts to address issues that Japan alone is unable to resolve. In a long-term,
assistance provided through the research platform will develop joint research and researchcooperation as well as facilitate the development of human resources specializing in thefields of radiation risks and radiation protection. The results produced through theresearch platform activities will ultimately be utilized for promoting the welfare, safety,
and health of the Japanese people.

Members of the Radiation Risk and Protection Research Platform Preparatory
Committee
Michiaki Kai; Chair

Oita University of Nursing and Health Sciences

Kotaro Ozasa

Radiation Effects Research Foundation

Keiji Suzuki

Nagasaki University

Hiroshi Tauchi

Ibaraki University

Hiroshi Yasuda

Hiroshima University

Masumi Yokoyama

Fujita Health University

Takashi Sugihara

Institute for Environmental Sciences

Toshiyasu Iwasaki

Central Research Institute of Electric Power Industry

Tatsuhiko Imaoka

National Institutes for Quantum Science and Technology

Acknowledgment
We would like to thank Dr. Otsura Niwa, Dr. Tomoko Kusama and Dr. Junko Nakanishi
for the Evaluation Committee, Dr. Kazuo Yoshida for helpful discussions, and Dr. Yutaka
Yamada, Dr. Tetsuo Nakajima, Dr. Michiya Sasaki and Ms. Yasuko Morimoto for clericalwork.