Making Sense of the 2026 Centers for Medicare and Medicaid Services (CMS) Radiation Oncology Treatment Delivery Codes: Historical Context and Practical Applications for Clinicians.

Medical billing and coding remain among the least understood aspects of daily practice for many physicians, including radiation oncologists. Legacy linear accelerator (LINAC)-based radiation treatment delivery codes have remained largely unchanged over the past decade, despite substantial advances in image guidance, intensity-modulated techniques, and motion management. This has drawn the attention of those empowered to insist upon updates to the coding and the amount of time involved in individual therapy administrations. In 2023, the American Medical Association's (AMA)/Specialty Society Relative Value Scale Update Committee (RUC) Relativity Assessment Workgroup (RAW) mandated re-evaluation of these codes and requested that radiation oncology (RO) specialty societies provide contemporary definitions, times, and resource information for treatment delivery services. The American College of Radiation Oncology (ACRO) and the American Society for Radiation Oncology (ASTRO) jointly developed a new complexity-based code set for megavoltage external beam radiation therapy (EBRT). The RUC subsequently surveyed physicians and recommended relative value units (RVUs). In October 2025, CMS finalized the use of this new code set, effective January 1, 2026. Written by ACRO members involved in the code development and valuation processes, this report places the 2026 code set in historical context and provides practical, physician-focused guidance on applying the new delivery Current Procedural Terminology® (CPT®) codes 77402, 77407, and 77412 (as well as 77387 for professional components of image guidance) in everyday practice. We also summarize the AMA and CMS process, define the complexity framework, and provide concrete clinical examples for appropriate code selection with an emphasis on image guidance, motion management, multiple isocenters, and mixed photon-electron techniques.