Kinetics of sup(99m)technetium-tin-methylene-diphosphonate in normal subjects and pathological conditions: A simple index of bone metabolism

The blood clearance and the urinary excretion of the bone scanning complex technetium-tin-methylene-diphosphonate sup(99m)Tc-Sn-MDP administered intravenously have been measured in 27 normal subjects and 104 patients with postmenopausal osteoporosis, osteomalacia, primary hyperparathyroidism, Paget's disease, pagetoid metastases of prostatic cancer, osteolyses, chronic renal failure, and liver cirrhosis to quantitative the skeletal uptake of the radiopharmaceutical. Kinetic analysis of the data was performed in terms of a four-compartment model; correspondent rate constants and fitted values were estimated. In normal subjects the whole-body retention (WBR) up to 24 h was 33.3% +- 7.4 SD, whereas significantly more elevated values were observed in several pathological conditions, the highest values being ascertained in patients with pagetoid metastases, primary hyperparathyroidism, and chronic renal failure and whenever large osteoid seams were present. Differences were found between osteoporosis and osteomalacia, monostotic and polyostotic Paget's, pagetoid and osteolytic metastases of bone. (orig./AJ)