Emergency Preparedness for External Beam Radiotherapy Machines: Treatment Continuity and Interruption Recovery in Radiation Oncology.

Unplanned radiotherapy interruptions can reduce treatment effectiveness, increase recurrence risk, delay symptom palliation, and complicate completion of the prescribed course. Effective preparedness requires strategies to prevent interruptions, limit their duration, and support safe completion of treatment when disruptions occur. This review frames emergency preparedness for external beam radiotherapy (EBRT) machines as a treatment-continuity challenge within the radiation oncology workflow. Relevant disruptions may arise from the treatment machine, simulator, imaging or image-guidance system, treatment-data pathway, room environment, or specialized workflow. Clinical significance depends on whether the intended fraction and treatment course can be delivered safely, accurately, and without clinically consequential interruption. We present a readiness, response, and recovery framework for EBRT machine preparedness. Key elements include patient-centered triage, machine and room capability mapping, image-guidance contingency planning, backup treatment pathways, minimum treatment-data requirements, partial-fraction review, selected infection-control lessons, centralized response coordination, and return-to-treatment checks.