DETECTION OF DIFFUSE SKELETAL LESIONS BY MONITORING THE KINETICS OF LABELED PHOSPHONATE

A method of detecting of diffuse skeletal involvement in patients with metastatic tumors or with metabolic diseases is presented. The study consisted of 31 patients without bone disease and of 26 selected patie nts with diffuse skeletal involvement. The kinetics of Tc-99m-dicarbox ypropane diphosphonate (DPD) were calculated by monitoring the plasma and urine concentrations up to 5 hours after administration. Using the se data, the renal clearance as well as the increase in urinary excret ion of Tc-99m-DPD were determined. The results indicate that measureme nt of the quantity of Tc-99m-DPD excreted in the urine after 3 hours a llows a reliable separation of the patients with diffuse skeletal lesi ons from normals. Other calculations such as renal clearance as well a s the drop in plasma concentration were less sensitive. The test may b e performed simultaneously with bone scintigraphy without additional r adiation burden to the patient.