Direct labeling of macroaggregated albumin with indium-111-chloride using acetate buffer.
Indium-111-labeled macroaggregated albumin (MAA) would be suitable for combined pulmonary perfusion and ventilation scan using a 99mTc ventilation agent.


METHODS
MAA suspended in 0.1 M sodium acetate buffer, pH 5.8, was incubated with 111In-chloride for 30 min at room temperature. An in vitro study of the obtained 111In-MAA was performed for labeling efficiency and stability in human normal serum. The 111In-MAA was intravenously injected into normal mice, and the biodistribution was studied at 15 and 180 min postinjection. A gamma camera image was obtained at 15 min after injection.


RESULTS
MAA was directly and stably labeled with 111In-chloride, and the labeling efficiency of the preparation was more than 96%. More than 90% of the administered 111In-MAA was caught in the murine lung. The scintigraphy with 111In-MAA showed a clearly visualized murine lung.


CONCLUSIONS
Indium-111-MAA can be conveniently prepared by direct labeling at room temperature. It provides an alternative perfusion tracer for combined perfusion-ventilation imaging.
Watanabe
N
N
Department of Nuclear Medicine, Gunma University School of Medicine, Japan.
Shirakami
Y
Y
Tomiyoshi
K
K
Oriuchi
N
N
Hirano
T
T
Higuchi
T
T
Inoue
T
T
Endo
K
K
D000818:Animals; D002021:Buffers; D005260:Female; D006801:Humans; D007204:Indium / Q000493:pharmacokinetics; D007205:Indium Radioisotopes; D007553:Isotope Labeling; D008168:Lung / Q000000981:diagnostic imaging*; D051379:Mice; D008807:Mice, Inbred BALB C; D011877:Radionuclide Imaging; D012709:Serum Albumin / Q000493:pharmacokinetics; D019346:Sodium Acetate; D014018:Tissue Distribution; D014692:Ventilation-Perfusion Ratio
D002021:Buffers; D007205:Indium Radioisotopes; D012709:Serum Albumin; D007204:Indium; C020758:indium trichloride; D019346:Sodium Acetate