In-House Preparation and Characterization of Ready-To-Use TC99m-Sn-Macroaggregated Albumin Kit for Lung Perfusion Studies

Macroaggregates of human serum albumin (HSA) are used as a basis for lung perfusion imaging. The present study involves in-house production of a macroaggregated HSA kit. A modified method for the preparation of Tin-macroaggregated albumin (Sn-MAA) kit, with high Tc99m labeling efficiency (>98%) was developed for lung perfusion studies. The aggregative condition of HSA was stabilized by adding 5 mg/ml polyvinyl pyrolidone (PVP 30, 2.5% solution) and gave a uniform particle size distribution in the range of 10- 60 m. The kits were lyophilized and the stability of both wet as well as lyophilized kits were studied at room temperature 8°C and 0°C. The results revealed that lyophilized kits were stable for up to six months and retained their particle size uniformity and labeling efficiency. Biodistribution studies in the animals gave excellent lung images, with >90% of the injected radiation dose accumulating in the lungs.