Despite advancements in cyber security, ransomware attacks have occurred in health care with devastating effects. In the last 5 years, an estimated 60,000 radiotherapy treatments have been impacted by ransomware attacks affecting Radiation Oncology departments. Our project starts from the assumption that ransomware attacks will occur, and asks the question: what can be done to resume radiation treatments as rapidly and safely as possible during and after an attack? We refer to this concept as ransomware attack resiliency. Radiation oncology is particularly susceptible to ransomware attacks because it is the most technology reliant medical discipline as the ability to safely deliver radiation therapy is heavily reliant on multiple complicated software systems. If a ransomware attack does occur, Radiation Oncology patients are critically impacted as inevitable delays in treatment result in worse clinical outcomes, complicated workarounds result in unsafe treatment conditions, and the attacks stressed aspects of clinical care (transportation and communication) that disproportionately impacted patients with adverse social determinants of health. Research into ransomware attack response in Radiation Oncology has been primitive. Our project will form a multi-disciplinary team and patient advisory board to develop innovative Radiation Oncology specific ransomware resiliency methods and tools. Aim 1 will develop design goals through structured interview of frontline staff, meetings with a patient advisory board, and by performing ransomware attack resiliency exercises by disabling software components needed to treat a patient (thereby mimicking a ransomware attack) and asking the team to treat simulated patients. The structured interviews will be evaluated using rigorous qualitative data from cognitive interviews and the resiliency exercises will be evaluated using quantitative metrics. Aim 2 will develop novel software functionality for ransomware resiliency including: 1) a robust Relational Backup System that innovatively generates a backup of essential relationships between data elements on multiple systems, 2) Record and Verify and treatment planning system minimum functionality algorithms, and 3) imaging checks based on artificial intelligence methods. A comprehensive ransomware management document will be developed with strategies for mitigating the impact of ransomware attacks on patients with adverse social determinants of health. Aim 3 will longitudinally implement the proposed innovations in diverse circumstances and iterate the development/evaluation cycle 4 times. We will implement the developed innovations from Aim 2 and repeat the structured interviews, meetings with the patient advisory board, and resiliency exercises. Our project can significantly improve outcomes for cancer patients receiving radiotherapy at institutions impacted by ransomware attacks. The innovations and methods from our work can reduce the time needed to return to safe...