Harnessing atomic particles and radiation led to powerful and world changing technologies. The field of medical imaging has saved countless lives and continues to push the boundaries of medical interventions and research, which would have been impossible without the first x-ray machines. Unfortunately, not all inventions have been so altruistic. The advent of nuclear weapons showed the world the destructive potential possible via scientific inquiry. While the dangerous effects of radiation exposure were documented from the inception of this technology, catastrophic events like the bombing of Hiroshima and Nagasaki and nuclear disasters at Chernobyl Semipalatinsk or Fukushima provide a real-time glimpse into the long-term effects of exposure. Investigating the causes of this exposure in order to prevent future accidents is essential, but so too is cataloguing the rates and types of exposure among the victims. With this information correlations between exposure and health effects, both short- and long-term can be interrogated. This data is crucial for the understanding of the mechanisms behind radiations effects on living creatures and in assessing risks, safety protocols and treatment. Dr Masaharu Hoshi, Professor Emeritus at the Hiroshima University, has spent most of his career travelling around the world, visiting the sites of nuclear disasters in an effort to fully comprehend the risks. He is now using case studies to investigate the radiation exposure and health effects of the residents of radioactive microparticles.