Dr. Tsubokura's Radiation Lecture Vol.150

Author: Masaharu Tsubokura M.D., PhD.

Editors: Akihiko Ozaki M.D.,PhD., Yuki Senoo MUDr.

299. No chromosomal alteration found in second-generation atomic-bomb survivors

October 10, 2020

Previous investigation demonstrated no detectable genetic effects, such as increased risks of cancer and other diseases, among the atomic bomb survivors’ offspring (the second generation of those who were directly exposed to radiation, also known as the second generation of atomic bomb survivors) in Hiroshima and Nagasaki. This article further explains the findings of these investigations, particularly those relating to the genetic effects on the survivors’ offspring, in detail.

To date, several investigations have been conducted to assess the chromosomal aberrations in the second generation of atomic bomb survivors. Chromosomes are bundles of tightly coiled structures within cells that contain a mass of genetic information.

In the investigations, the incidence of genetic abnormalities in children whose parents received a high dose of radiation exposure near the hypocenter at the time of the atomic bomb explosion was examined and compared with those of children whose parents were out of Hiroshima City and/or far from the hypocenter at the time of the explosion.

The results of these investigations demonstrated that there was no difference in the incidence of chromosomal abnormalities between children whose parents received high-dose radiation exposure near the hypocenter and those whose parents did not.

Besides, further investigation on the genetic testing of the parents and siblings of those children with chromosomal abnormalities confirmed that the majority of the chromosomal aberration were not newly produced by radiation damage but inherited from one of the parents.

Thus, these results provide strong evidence to support that radiation contamination caused by the 2011 Fukushima Daiichi nuclear power plant accident was not at a level to cause concern about genetic effects.

300. A basic understanding of radiation clears up radiation misconception

October 27, 2020

This series of local newspaper articles started with a piece explaining that the impact of radiation on health is determined by the extent of the exposure, not by the mere occurrence of exposure. There was also a piece discussing the difference between radiation and radioactive materials.

Think of radiation and radioactive material as a sparkler; the burning part of the sparkler at the center is radioactive material, and the sparks scattered around the sparkler are radiation. Like radiation, sparklers illuminate space and scatter bright sparks. Then, gradually, the brightness weakens, and the fire burns out. In addition, the property of certain substances to emit sparks (radiation) is called radioactivity.

One can also compare radioactivity, radiation, and radioactive material to a flashlight. The flashlight is radioactive material, the light emitted from the flashlight is radiation, and the flashlight’s ability to emit light is called radioactivity. In some cases, radioactive material is also called radioactivity.

Furthermore, alpha rays, beta rays, and gamma rays are types of radiation, and the substances that can emit these rays, such as cesium, iodine, radon, and potassium, are radioactive materials.

Therefore, the substances that were spread into the surrounding environment due to the 2011 Fukushima Daiichi nuclear power plant were radioactive materials, not radiation. Further, the substance that our bodies were exposed to was radiation, not radioactive materials, and the food investigations conducted in the prefecture measured the amount of radioactive materials present, not radiation.

This work gives a basic understanding of radiation, and I strongly believe that understanding this kind of basic knowledge can reduce prejudice, clear up misconceptions of radiation, and support people to move forward in their lives. Last but not least, I would like to express my heartfelt gratitude to everyone who has provided me support and guidance.

(Masaharu Tsubokura MD, PhD, Professor of Radiation Health Management, Fukushima Medical University)