Andrew J. Tofe

Inorganic tin: Chemistry, disposition and role in nuclear medicine diagnostic skeletal imaging agents

Abstract A brief review of the chemistry of tin(II) is made with particular emphasis on oxidation and hydrolysis. Spurious oxidation and hydrolysis of tin(II) are reactions encountered in conjunction with the radionuclide technetium which can be important in scintiscan quality and interpretation under use conditions in nuclear medicine. Means to block these reactions are discussed. Some reactions of tin(II) and phosphonates of general interest are examined. The toxicity and biological handling of both tin(II) and tin(IV) are reviewed. Recent methods of reducing and complexing technetium without the use of tin(II) are discussed.

Factors Affecting Uptake and Retention of Technetium-99m-Diphosphonate and 99m-Pertechnetate in Osseous, Connective and Soft Tissues

The bone scanning complex,99mTc−Sn·EHDP, consisting of the nuclide technetium-99m, stannous ion and ethane-1-hydroxy-1,1-diphosphonate, administered intravenously is retained in soft tissues in proportion to increasing calcium content of the tissues. Within bone tissue, the retention is proportional to vascularity and to surface area of calcium phosphate in bones and not necessarily to calcium and phosphate concentration. The nuclidic agent99mTcO4− but not the99mTc-diphosphonate is selectively taken up by the thyroid and this uptake can be blocked by administering sodium perchlorate. Among the connective tissues studied, the tracheal cartilage seems to have the greatest potential to calcify with increasing age of the animal and man. Soft tissue does not retain the bone scanning complex99mTc−Sn·EHDP but does retain99mTcO4−.