OSTEO: A Plan Evaluation Framework for Low-Dose Radiation Therapy in Osteoarthritis.

Low-dose radiation therapy (LDRT) for osteoarthritis (OA) is an emerging treatment modality in the United States, yet standardized methods for treatment plan evaluation are lacking. Existing plan evaluation tools were developed primarily for malignant disease and do not address the unique considerations of LDRT for non-malignant conditions. We developed OSTEO, a framework designed to assess essential components of OA LDRT plans during plan review. The OSTEO acronym represents five evaluation criteria: Overdose, Size, Target coverage, Epicenter, and Orientation. A complementary scoring rubric organizes these criteria into three domains to quantify plan quality. We validated this framework through independent evaluation of 42 LDRT plans for knee OA by four radiation oncologists at a single institution. Inter-rater reliability was high, demonstrating consistent scoring across reviewers. The OSTEO framework provides a practical method for evaluating OA LDRT plans and supports quality assurance and standardization as clinical adoption of LDRT grows.