Cybersecurity of linear accelerators in radiation oncology beyond ransomware

The rapid digitalization of radiation oncology has enabled transformative advances but also introduced new vulnerabilities for millions of cancer patients. While most reported cyberattacks in healthcare have involved ransomware, the potential compromise of linear accelerators (LINACs) would pose a far greater risk to patient safety. This review examines cybersecurity challenges in radiation oncology with a focus on LINACs. We analyze the anatomy of potential attacks and their implications to raise awareness of stealth threats. We describe LINACs typical network topology and relevant clinical workflow to identify critical assets, vulnerabilities, and attack vectors. We then explore defence mechanisms and real-world best practices, emphasizing that although radiotherapy benefits from mature safety practices and strong clinical safeguards, proactive measures are still needed to anticipate cyber threats and strengthen system resilience. Immediate adoption of a multilayered zero-trust security architecture, supported by robust vendor and regulatory measures, is essential to protect patient safety and maintain clinical continuity in an evolving threat landscape.