Assessment and interpretation of radiopharmaceutical joint imaging in an animal model of arthritis.

An animal model of arthritis in the rabbit was employed to assess the radioactivity contribution of joint tissues to externally monitored scintigram positivity. Bone contained the greatest total amount of radioactivity whether the imaging agent was technetium pertechnetate or pyrophosphate, although the greatest percent increase in the arthritis joints over control joints was seen in synovium. Mid-shaft bone in the same region as the arthritic joint also showed increased radioactivity compared with control.