Quantitative scintigraphy using radiophosphate and radiogallium in patients with rheumatoid arthritis

Quantitative scintigraphy of the wrist, MCP, and knee joints in patients with RA was performed using Tc-99m-MDP and Ga-67 citrate. Radiopharmaceutical uptake in affected joints was compared with uptake at 2 control reference sites (juxta-articular bone and soft tissue). Following a 6-week course of therapy with Sulindac, the patients' overall assessment of disease was improved, but the results of joint/bone and joint/soft tissue ratios were variable. Improvement using Tc-99m-MDP during the first 2 weeks of NSAID therapy was noted in the minimally inflamed wrist by joint/soft tissue measurement and in the maximally affected MCP joint by joint/bone ratio. There was no change in the joint ratios employing the Ga-67 citrate radiopharmaceutical. The initial qualitative score assigned to a joint using Tc-99m-MDP was in agreement with the calculated quantitative ratio except for the knee joint. Our results suggest that quantitative scintigraphy in its present format cannot be used as a reliable indicator to monitor the course of rheumatoid arthritis during NSAID therapy and subjective measurements are still the best judge of effective treatment.