Significant differences among the /sup 99m/Tc-polyphosphates, /sup 99m/Tc-pyrophosphates, and /sup 99m/Tc-diphosphonates for bone imaging

The technetium-labeled phosphate and diphosphonate complexes are the primary radiopharmaceuticals currently used for diagnostic bone imaging. Replacing the radioisotopes of strontium and fluorine, these labeled complexes provide significantly improved bone image quality for diagnostic studies. Furthermore, imaging times are shorter and the radiation dose to the patient is generally less. This has resulted in a dramatic increase in the use of bone imaging as a diagnostic screening procedure. Investigations of the comparative clearance of these labeled compounds, in both experimental animal and patient studies, have shown that distribution characteristics can be affected by the following: (1) The time of imaging post-administration, (2) the delay between preparation and administration, and (3) the particular phosphate or diphosphonate preparation used. A review of these observations and their significance is correlated with the clinical application of the bone imaging procedure.