Normal pharmacokinetics of 99mTc-diphosphonate after intravenous administration

In the past several years bone imaging has become a routine diagnostic tool for the nuclear medicine clinician. However, increased information may be derived by determinating the radio‐pharmacokinetic parameters associated with blood, urine, and bone. In an adult male population of normals (N = 5–6) blood clearance, urinary excretion, and skeletal uptake of 99mTc‐Diphosphonate were determined as a function of time after intravenous (i.v.) administration. The quantitative imaging studies (lower lumbar region) were performed up to 1 h post administration with a scintillation camera interfaced to a computer. Blood levels exhibited a triexponential clearance pattern and urinary excretion of the radiopharmaceutical was essentially complete by 4 h. The computer‐generated images showed an initial early uptake in bone, kidneys, and soft tissue. Thereafter, a parallel fall‐off in activity was observed in kidneys and soft tissue, with a concomitant increase in bone.