Regulatory Science Considerations for Medical Countermeasure Radiation Biodosimetry Devices (Day 1) In the event of an accident or terrorist attack that exposes a large population to radiation, an accurate assessment of the absorbed ionizing radiation dose received by victims will be essential for triage and medical management. Because there is currently no cleared or approved radiation biodosimeter for use in a mass exposure scenario, the development of proper radiation biodosimetry tools is a critical unmet public health need. As such, FDA is holding this public meeting to obtain input from academia, Government, industry, and other stakeholders on the clinical application and scientific and technological challenges for performance validation of radiation biodosimetry devices. The ultimate goal of the meeting is to identify and seek solutions for the scientific challenges associated with radiation biodosimetry development, and clarify the regulatory path forward to ensure device safety and effectiveness and thereby provide significant clinical and public health benefits. (Javascript is required to view Mediasite content)