Preparation of yttrium-90-labeled human macroaggregated albumin for regional radiotherapy.
Human macroaggregated albumin (MAA), which is currently labeled with technetium-99m (99mTc) and 99mTc-MAA, is used clinically as a pulmonary perfusion agent and was directly labeled with yttrium-90 (90Y)-acetate. This study evaluated whether 90Y-MAA could be potential radiotherapeutic agent for regional radiotherapy against malignant tumors. MAA suspended in 0.1 M sodium acetate buffer, pH 5.8, was incubated with 90Y-acetate and purified in order to get rid of unstable binding of 90Y by electrophoresis. The radiochemical purity of 90Y-MAA in normal human serum was estimated by an agarose electrophoresis method and was more than 94% over 168 h in vitro. Following the intratumoral administration of 90Y-MAA, the time course of tumor radioactivity and the biodistribution in nude mice bearing human neuroblastoma were investigated up to 168 h. More than 93% of the radioactivity of the injected dose was found on the subcutaneous tumor over 168 h. The bone radioactivity was shown as 0.06 +/- 0.03% injection dose/gram tissue (% ID/g) (n = 5) at 24 h, 0.73 +/- 0.20% ID/g at 72 h, 0.92 +/- 0.16% ID/g at 120 h, and 2.51 +/- 0.59% ID/g at 168 h. A slight increase in radioactivity was noted in the liver, kidneys, and spleen over the 168-h periods. In conclusion, 90Y-MAA may be a potential agent for regional radiotherapy (brachytherapy) because of the sufficient persistence in the tumor following an intratumoral administration.
Watanabe
N
N
Department of Nuclear Medicine, Gunma University, School of Medicine, Japan.
Oriuchi
N
N
Igarashi
H
H
Higuchi
T
T
Yukihiro
M
M
Fukushima
Y
Y
Tomiyoshi
K
K
Hirano
T
T
Inoue
T
T
Endo
K
K
D000418:Albumins / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000818:Animals; D001918:Brachytherapy; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009369:Neoplasms / Q000532:radiotherapy*; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D015021:Yttrium Radioisotopes / Q000627:therapeutic use*
D000418:Albumins; D015021:Yttrium Radioisotopes