Since the events of 9/11, a concerted interagency effort has been undertaken to create comprehensive emergency planning and preparedness strategies for management of a radiological or nuclear event in the US. These planning guides include protective action guidelines, medical countermeasure recommendations, and systems for diagnosing and triaging radiation injury. Yet, key areas such as perception of risk from radiation exposure by first responders have not been addressed. In this article, we identify the need to model and develop new strategies for the medical manage-ment of large-scale population exposures to radiation, examine the phenomena of radiation dread and its role in emergency response, and review recent findings on the willingness to work of first responders and other personnel involved in mass casualty medical management during a radiological or nuclear event.