Abstract
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Objectives Radioactive microspheres radioembolization offers promise for treatment of liver cancer. The aims of this study were to establish a method for labeling HSA microspheres with 188Re by using the 188Re(I)-tricarbonyl ion ([188Re(OH2)3(CO)3]+) as a precursor at appropriate temperature. The evaluations of in vitro stability of 188Re-HSA microspheres and maximum tolerated dose (MTD) of 188Re-HSA microspheres in F344 male rats were performed.
Methods HSA microspheres were synthesized by gradually-heating method and analyzed with scanning electron microscope. [188Re(OH2)3(CO)3]+ was employed as a precursor for directly labeling HSA microspheres with 188ReO4-. 188Re-HSA microspheres were incubated in rat plasma at 37oC and normal saline at room temperature. The stability of 188Re-HSA microspheres was performed at 1, 4, 24, 48 and 72 h. Twelve of male F344 rats were injected with escalating activities (2.26 mCi to 9.5 mCi) of 188Re-HSA microsphere via hepatic artery route. The body weight and survival of rats were monitored twice a week over 1 month.
Results The shape of HSA microspheres was rough surfaced sphere or oval-shaped. The size of HSA microspheres was distributed between 20~35 μm. The yield of [188Re(CO)3(OH2)3]+ was 75~80%. The labeling efficiency of 188Re-HSA microspheres was more than 85%. According to body weight and survival results, the MTD of 188Re-HSA microspheres was 9.54 mCi in normal F344 rat.
Conclusions This study indicated that the advantages of convenient for manufacturing, high in vitro stability, and capability of radiotherapy and diagnosis for available multi-dose treatment.