Adaptive Response: A Scoping Review of Its Implications in Medicine, Space Exploration, and Beyond.

Objectives: Radiation Adaptive Response (AR) is a biological phenomenon in which exposure to low-dose radiation (LDR) enhances an organism's ability to withstand subsequent higher doses. This scoping review explores AR across multiple disciplines, summarizing evidence, identifying research gaps, and evaluating potential applications in cancer therapy, neurodegenerative disease management, space medicine, and pandemic response. Methods: A comprehensive review of experimental/clinical studies on AR was conducted, focusing on molecular mechanisms, biological implications, biophysical modeling, and translational applications. Results: In oncology, AR has shown promise in selectively protecting normal tissues during radiotherapy while sensitizing tumor cells, yet its effects remain cell-type dependent. LDR may manage neurodegenerative diseases by modulating oxidative stress and inflammation. In space medicine, AR-based astronaut selection has been proposed as a novel strategy to mitigate radiation risks during long-term space missions, although empirical validation is lacking. LDR therapy for managing COVID-19 pneumonia has been explored, but ethical concerns and long-term safety risks require further investigation. Conclusion: Despite AR's potential, its clinical and spaceflight implementation requires mechanistic elucidation, standardized protocols, and rigorous studies. The risks of tumorigenesis, individual variability in AR, and potential immunomodulatory effects must be evaluated before widespread application. Moreover, inconsistent AR appearance complicates its study and clinical use.