The purpose of this Notice of Funding Opportunity (NOFO) is to support exploratory and conceptual research projects in radiation research focused on medical countermeasures, biodosimetry, and animal model development to diagnose/mitigate/treat injuries arising from radiation exposure during a public health emergency. This NOFO is intended to support development of preliminary data to help advance high-risk, high-reward projects needed for a robust early product development pipeline that can lead to the advancement of much-needed radiation-exposure related tools and products.