Humanitarian Health Action

FAQs: Japan nuclear concerns

September 2011

Ionizing radiation

What is ionizing radiation?

  • When certain atoms disintegrate, they release a type of energy called ionizing radiation. This energy can travel as either electromagnetic waves (i.e. gamma or X-rays) or as particles (i.e. alpha, beta or neutrons).
  • The atoms that emit radiation are called radionuclides; e.g., radioactive iodine, caesium, and plutonium.
  • Ionizing radiation is an essential tool for diagnosis and treatment in medicine, that must be used with rigorous attention to safety.