Not every person with osteoarthritis is an appropriate candidate for low-dose radiation therapy (LDRT). The criteria below come from the 2026 American Radium Society Appropriate Use Criteria (ARS AUC) — a formal evidence review and multispecialty consensus document developed using a RAND-UCLA modified Delphi process, involving radiation oncologists, rheumatologists, orthopedic surgeons, and a patient advocate.
The Kellgren-Lawrence (KL) scale grades osteoarthritis severity on X-ray from 0 (normal) to 4 (severe). KL 0: no X-ray findings, though pain may be present. KL 1: doubtful changes, uncertain significance. KL 2: minimal — definite osteophytes (bone spurs), possible joint-space narrowing. KL 3: moderate — definite osteophytes, marked narrowing, some sclerosis. KL 4: severe — large osteophytes, marked narrowing, severe sclerosis, possible bone deformity. LDRT is generally used across KL grades 1 through 3. Symptomatic KL 0 to 2 patients are also appropriate candidates as adjunctive therapy. Patients with KL grade 4 disease may also be considered — response rates are expected to be lower, but the ARS AUC notes limited data exist to quantify that difference and explicitly contemplates LDRT in advanced disease for patients who have exhausted other options and are not surgical candidates.
The best evidence for LDRT is in large joints: the knee (most-studied, multiple randomized controlled trials and large retrospective series), hip (well-represented in European series), and shoulder (strong European data). Hands, fingers, feet, and ankles may benefit, but evidence is more limited. The spine has limited or no published data and the ARS AUC recommends caution for spinal osteoarthritis.
LDRT targets the inflammatory and degenerative process specific to osteoarthritis. Rheumatoid arthritis and psoriatic arthritis are systemic autoimmune diseases driven by immune dysregulation — a fundamentally different mechanism. These conditions require disease-modifying antirheumatic drug (DMARD) therapy, not radiation. If you have been diagnosed with RA or PsA, discuss management with a rheumatologist.
The ARS AUC is explicit: LDRT is not a first-line treatment. It is considered after chronic pain has persisted beyond 3 to 6 months despite measures such as activity modification, weight management, physical therapy, acetaminophen, oral or topical NSAIDs, and intra-articular injections. The AUC notes that multimodality lifestyle management achieves response in fewer than 50 percent of patients, and roughly 25 percent of patients requiring pharmacologic treatment will not respond or lose responsiveness over time. LDRT fills this treatment gap.
The ARS AUC recommends that patients discuss LDRT candidacy with their existing medical team before referral to radiation oncology. Appropriate referring physicians include primary care physicians, rheumatologists, orthopedic surgeons, and sports medicine physicians. A radiation oncologist will review imaging, confirm the OA diagnosis and KL grade, and discuss whether LDRT is appropriate for your specific situation.
Related pages: Radiation safety and cancer risk | Side effects and what to expect | Cost and insurance coverage | Find an LDRT provider
Medically reviewed by: Robert Warren Floyd, M.D., Ph.D. — Resident Physician, Radiation Oncology, The University of Texas MD Anderson Cancer Center. Last reviewed: August 2, 2026. Independent personal project — not affiliated with or endorsed by MD Anderson Cancer Center. Funding & independence disclosure.