Bone scintigraphy using 99mTc-MDP was performed on 2 patients with Paget's disease of bone before and after the treatment with a synthetic eel calcitonin analogue ( (Asu1, 7) -eel calcitonin, ECT) ) at a dose of 40 U per day. All pagetie lesions showed markedly the increased accumulation of the radionuclide. The uptake ratio, defined as the count rate of 99mTc-MDP over each bone lesion to that over the control bone, was calculated. The response to the calcitonin therapy was evaluated with the uptake ratio of the radionuclide. The uptake ratio decreased markedly within the first 3 months of the treatment, in association with a palliation of bone pain, while the serum alkaline phosphatase activities which had been within the normal range or slightly high before the treatment did not show any significant change or did not reflect a clinical feature (e.g, bone pain) with the treatment. Thus, the uptake ratio on the bone scintigram seemed to offer the most sensitive and most reliable information for the evaluation of calcitonin treatment of Paget's disease of bone.
