Accident of radiation exposure and/or contamination with radionuclide

The accident of exposure is defined to be an unintentional one leading to deleterious outcome. This paper reviews the historical and recent accidents involving those mainly dealt in National Institute of Radiological Sciences (NIRS) in Japan and reported in foreign countries, and describes Japanese medical system for coping with the exposure. Hazardous events of radiation exposure are reported as early as within 1 year after discovery of X-ray by Roentgen (1895). In Japan, there are accidents of exposure to the crew of fishing boat Daigo Fukuryu Maru by nuclear experiment at Bikini Atoll (1954), of exposure by stolen ¹⁹²Ir source (1972) and by Tokai Criticality Accident (1999). More recently, accidents dealt in NIRS are 13 incidents in 2000-2011: serious cases are 3 skin injuries of electronic industry workers by soft X-ray at 50-91 Gy (2000), and of a high school student at 9 Gy (2001) in the science lesson. The decontamination, dosimetry, radiological protection and support of temporary entrance of evacuees have been conducted by NIRS at Fukushima Nuclear Power Plant Accident (2011). Foreign information of 19 severely exposed accidents from 2000 to 2012 are described partly or thoroughly for 18 countries. In Japan, the medical system for coping with the exposure is now under re-construction on the impact of the Fukushima Accident. Its concept stands on the aspects that the system is essentially built up not only for prefectures having nuclear power plant and their neighboring ones, but also those with facilities dealing with radioisotopes, and that those undertaking subjects are thoroughly responsible for concurrent support of medicare at radiation emergency. The guideline for medical education published in 2011 contains the item concerning the radiation/humans. (T.T.)