The radiopharmaceutical chemistry of 99mTc-tin fluoride colloid-labeled-leukocytes.

Tc-99m-tin fluoride colloid is a radiotracer used to label patient white cells, for the diagnosis of infection and inflammation. The scintigraphic technique has been employed in routine clinical practice for approximately 20 years in Australia, yet the chemistry of the radiolabeling agent, and the physiological distribution of (99m)Tc-leukocytes, are not entirely understood. In this review, the physico-chemical characteristics of (99m)Tc-tin fluoride colloid are discussed, as well as the in vitro and in vivo distribution of (99m)Tc-tin fluoride-labeled-leukocytes. Furthermore, important animal and human studies are summarized, that emphasize the clinical usefulness of this radiopharmaceutical tracer in nuclear medicine today.