Rheumatoid arthritis (RA) is a chronic inflammatory joint disease that causes chronic synovial inflammation. Reactor-producedβ-particle emitting radionuclides is a new therapeutic strategy in the management of RA. This study was conducted in 2019and analyzed the toxicity and feasibility of 188Re-tin colloid injection, Three-Phase Positive Bone Scan, and Refractory KneePain. Ten patients with RA were administered radiosynovectomy with 188Re-tin colloid. The main complications after theintervention were assessed and compared with patients’ pre-intervention condition. Patients showed alleviation of pain,tenderness, and morning stiffness after the administration of radiosynovectomy. Only one RA patient received a corticosteroidinjection; the other 6 patients did not need a corticosteroid injection after radiosynovectomy. Intra-articular 188Re-tin colloidinjection seems to be an effective treatment modality for refractory knee joint pain in rheumatoid arthritis patients. Thus, it issuggested as a safe and effective strategy to apply.