Stability of Filtered Technetium Tc-99m Sulfur Colloid

Abstract

Filtered technetium Tc-99m–labeled sulfur colloid has recently gained popularity for use in lymphoscintigraphic mapping of lymphatic flow and identification of sentinel lymph nodes.1–6 Little has been published, however, regarding the stability of filtered Tc99m sulfur colloid. Corrigan et al.7 reported that the filtration procedure resulted in a significantly lower radiochemical purity but that no change in the radiochemical purity of the filtered Tc-99m sulfur colloid was measured over the next 6 hours. Hung et al.8 reported that the filtration procedure resulted in a slightly lower radiochemical purity, and that the radiochemical purity of the filtered Tc-99m sulfur colloid decreased slightly over 6 hours. No information regarding sedimentation/adsorption to container wall or change in particle size (e.g., aggregation or clumping) has been reported for filtered Tc-99m sulfur colloid.