RERF Report No. 12-14

Paper published in Health Physics§“A Report from the 2013 International Symposium: The Evaluation of the Effectsof Low-Dose Radiation Exposure in the Life Span Study of Atomic BombSurvivors and Other Similar Studies”
Grant EJ, Ozasa K, Ban N, de González AB, Cologne J, Cullings HM, Doi K, Furukawa K,Imaoka T, Kodama K, Nakamura N, Niwa O, Preston DL, Rajaraman P, Sadakane A, Saigusa S,Sakata R, Sobue T, Sugiyama H, Ullrich R, Wakeford R, Yasumura S, Milder CM, Shore RE
Health Physics 2015 May; 108(5):551-6(doi: 10.1097/HP.0000000000000262)

Introduction
In December 2013, an International Symposium was held at Hiroshima RERF to discuss
the effects of low-dose radiation exposure among the atomic bomb survivors and others exposed
to low-dose radiation such as Chernobyl residents, Fukushima prefecture residents, andradiation workers.
Explanation
Top radiation scientists from Japan and the USA met at RERF for a two-day symposium todiscuss the low-dose effects of radiation. Risk of cancer occurrence after radiation exposure isusually expressed as a percentage increase above the “background” risk among persons without
radiation exposure. The risk generally rises in linear fashion as the radiation dose increases.
There is a range of radiation doses for which such effects are clearly evident. However, withsmaller radiation doses, the increase in risks above the background rates of cancer incidence
becomes less pronounced and thus more difficult to identify.
The symposium was an opportunity to discuss this issue and create strategies to try andquantify the risks of low-dose radiation exposure, a theme that RERF is working to explore in
more detail. Topics discussed included the current status of low-dose risk detection, strategies
for low-dose epidemiological and statistical research, the value of fostering communication
between epidemiologists and biologists, and the current status of radiological studies and tools.
RERF’s Life Span Study (LSS) data will continue to provide additional information as thecohort’s follow-up is continued over time. However, despite the comprehensiveness of this LSS
data, the members of the symposium agreed that more data were needed and that researchorganizations will need to pool their data to gain a fuller understanding of the health effects oflow-dose radiation, as no single study can likely resolve this complex issue on its own.

The Radiation Effects Research Foundation has studied A-bomb survivors and their offspring in
Hiroshima and Nagasaki for more than 60 years. RERF’s research achievements are considered theprincipal scientific basis for radiation risk assessment by the United Nations Scientific Committee on theEffects of Atomic Radiation (UNSCEAR) and for recommendations regarding radiation protection
standards by the International Commission on Radiological Protection (ICRP). RERF expresses its
profound gratitude to the A-bomb survivors and survivors’ offspring for their cooperation in our studies.
§Health Physics, the monthly journal of the Health Physics Society, publishes peer-reviewed original andreview articles addressing radiation effects and related issues in the fields of physics, chemistry, biology,and medicine. (Impact factor in 2013: 0.774)

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