To date, many major radiation accidents have occurred worldwide, mostly in nuclear reactors, and some other minors in radioactive isotope production facilities and during the transport of radioactive materials. Similarly, the majority of the radiation accidents in Turkey occurred in industrial radiology or during the use of sealed radioactive sources for the purpose of non-destructive testing. However, only a few of them happened in medical practices. In case of fire in buildings with radioactive material, terrorist incidents using radioactive materials, or accidents during transportation of radioactive materials, emergency response teams, first aiders and firefighters may be exposed to low-level radiation while performing their duties. Fortunately, very few victims of radiation accidents develop acute radiation syndrome and require medical intervention. On the other hand, some victims of radionuclear accidents may require urgent medical intervention since the adverse health effects may occur years after the event due to internal contamination and following incorporation. In this report, we aimed to define the basic concepts of radionuclear emergency and medical management of radionuclear victims.