Technetium-99m-human serum albumin: evaluation of a commercially produced kit

Results are reported on the use of a commercial kit for the labeling of human serum albumin with 99mTc. One-hour blood levels obtained in 20 subjects undergoing gated cardiac imaging were found to be 46.0 +/- 10.5% (s.d.) of the administered dose. The highest labeling efficiencies (94.2 +/- 9.3%) were obtained when human serum albumin 25% (salt-poor) was used. Satisfactory nuclear cardiac ventriculographic images were obtained in patients receiving the radiopharmaceutical when the labeling efficiency was at least 85%. Occasional batches were milky in appearance, contained black particulate matter, were acidic, or contained a high percentage of unbound 99mTc activity. Although this kit makes 99mTc-human serum albumin accessible to most nuclear medicine facilities for general clinical use, an active quality control program is required prior to use in patients.