Modified pyrophosphate-Tc-99m kit for application in nuclear cardiology

Abstract

A modified Tc-99m(Sn)-pyrophosphate (PyP) kit for the application in nuclear cardiology (radioventriculography, angiocardiography, scintigraphy of blood pool) was developed. Each vial contains 12 mg PyP (Na4P2O7), 4 mg SnCl2. 2H(2)O, 2.5 mg gentisic acid and IO mg NaCl. The reconstitution is performed by dissolving the lyophilized kit in 3 mi 0.9% NaCl. In comparison with the standard pyrophosphate kit for bone scanning and detection of miocardial infarction, it contains an increased amount of Sn(Il) so that the molar ratio ligand/reductant is lowered from 25 to 2.5. The radiochemical analyses showed that the radiochemical purity of the labeled kit is high ( GT 90%) during three hours after addition of Tc-99m-activity. The shelf-life of the inactive freeze-dried preparation is up to four months providing that it is kept in vacuum and at appropriate temperature (2-8 degrees C). The biodistribution studies revealed increased accumulation in blood and low uptake by liver and kidneys. It was concluded that the modified kit performs stable and reproducible properties.