Japanese and Russian scientists to conduct joint research on internal radiation exposure to probe impact on human body

by Michiko Tanaka, Staff Writer

Scientists from Hiroshima and Russia have made the decision to pursue joint research on the problem of internal exposure to radiation. The scientists will seek to clarify the actual impact on the human body of the internal exposure to radiation arising from the atomic bombing of Hiroshima and other incidents, as many aspects of its effects have yet to be properly understood.

On the Hiroshima side are scientists Masaharu Hoshi, a professor emeritus at Hiroshima University and a specialist in radiation biology and physics, and Megu Ohtaki, a professor of applied statistics at Hiroshima University’s Research Institute of Radiation Biology and Medicine (RIRBM).

The two Japanese scientists proposed the joint research at a meeting to discuss internal exposure to radiation, held in the city of Hatsukaichi, Hiroshima Prefecture, on February 3. Five Russian physicists who attended the meeting, including Sergey Shinkarev from the Burnasyan Federal Medical Biophysical Center, a research institution affiliated with the Russian government, expressed their support for the idea.

One theme of this research involves the impact of radioactive dust stirred in the atomic bombing of Hiroshima, which covered a wide area. Professor Hoshi has been collecting soil samples in the city of Hiroshima to simulate how the dust flew in the air at the time of the bombing. Russian scientists will join a procedure designed to estimate the area affected by the dust as well as the dose of internal radiation.

In addition, the scientists will share data on the “black rain” which fell in the aftermath of the atomic bombing and the accident at the Chernobyl nuclear power in 1986, in the days of the former Soviet Union, to aid their probe into the consequences of internal exposure. The participants have decided to hold their next meeting at the same time next year to report on the developments of this research.

After conducting an analytical study of data obtained on A-bomb survivors, a group led by Professor Ohtaki has determined that indirect exposure as a result of residual radiation and radioactive fallout, such as the black rain, may have significantly raised the risk of death by solid cancers over the initial dose of radiation received at the time of the explosion for those who were exposed to the bomb’s radiation at a radius of about 1.2 to two kilometers from the hypocenter.

“There are some cases which cannot be explained by the initial dose of radiation alone, occurring at the time of the blast, as some people suffered hair loss while in locations away from the hypocenter,” said Professor Hoshi. “We would like to share our findings to help clarify what happened.”

(Originally published on February 4, 2013)