Influence of Different Parameters on the Labeling Efficiency of 99mTc-Radiopharmaceuticals: Kuwait Nuclear Medicine Departments Experiences

To evaluate the effects of temperature, light, pH, reducing agents, oxygen, dilution, syringe material, solvents, and operator differences on the labeling efficiency of 99mTc-radiopharmaceuticals. Five GE Healthcare kits ([99mTc]Tc-HMPAO, [99mTc]Tc-MAA, [99mTc]Tc-DMSA, [99mTc]Tc-DTPA, and [99mTc]Tc-Tin colloid) were reconstituted with 99mTc-pertechnetate in saline and tested under varying conditions. Labeling efficiency was largely unaffected, except for [99mTc]Tc-HMPAO, which showed significant reductions with temperature changes (p<0.001). UV light significantly degraded labeling in all kits (p<0.001), and pH changes reduced [99mTc]Tc-DMSA efficiency. Stability depends on optimized formulation, storage, and preparation, and shelf-life extension may be feasible under controlled conditions.