Abstract
Technetium-99m sulfur colloid (99mTc-SC) has been useful in reticuloendothelial imaging, and in particular in liver/spleen and more recently bone marrow scintigraphy. Technetium-99m SC can also be employed to localize acute gastrointestinal bleeding and has been used in lung ventilation studies. The standard radiolabeling method requires a heating period in a boiling water bath. A comparison of a standard boiling technique (5 min) and a microwave technique (20 sec) for the preparation of 99mTc-SC was performed. Radiochemical purity results and particle sizing data were analyzed, and a qualitative visual assessment of the change from a clear solution to an opaque one was performed. Both methods of preparation routinely yielded products with greater than 97% bound, particle sizing of greater than 82% between 0.1 μm and 1.0 μm, and a consistent opaque appearance of the radiopharmaceutical upon completion. Preliminary evaluation in patients demonstrated rapid blood clearance and excellent images. Microwave heating significantly reduces preparation time and yields a consistently acceptable radiopharmaceutical.
