As the world shut down in reaction to the COVID-19 pandemic in April 2020, many radiation oncologists began collaborating to revive a decades-old use of ionizing radiation therapy on a clinical trial to try to help with COVID-19 pneumonia. Using low dose radiation therapy (LDRT) for a non-malignant disease based upon historical data has been highly controversial, but this debate has helped revive questions about the role of radiation therapy in medicine in ways that deserve deeper consideration. The aim of this paper is to provide some historical and scientific perspective on perceptions of radiation therapy and its risks, including questioning the linear no threshold (LNT) hypothesis and the emergence of data on radiation hormesis. The hope is that this review may stimulate debate on whether to expand the use of low dose radiotherapy (LDRT) beyond its current use primarily for neoplastic disease. Areas of interest include the potential use of LDRT for neurodegenerative, neuroinflammatory, autoimmune disease and for acute injury.