Imaging, Autoradiography, and Biodistribution of 188Re-Labeled PEGylated Nanoliposome in Orthotopic Glioma Bearing Rat Model

Abstract The 188Re-labeled pegylated nanoliposome (abbreviated as 188Re-Liposome) was prepared and evaluated for its potential as a theragnostic agent for glioma. 188Re-BMEDA complex was loaded into the pegylated liposome core with pH 5.5 ammonium sulfate gradient to produce 188Re-Liposome. Orthotopic Fischer344/F98 glioma tumor-bearing rats were prepared and intravenously injected with 188Re-Liposome. Biodistribution, pharmacokinetic study, autoradiography (ARG), histopathology, and nano-SPECT/CT imaging were conducted for the animal model. The result showed that 188Re-Liposome accumulated in the brain tumor of the animal model from 0.28%±0.09% injected dose (ID)/g (n=3) at 1 hour to a maximum of 1.95%±0.35% ID/g (n=3) at 24 hours postinjection. The tumor-to-normal brain uptake ratio (T/N ratio) increased from 3.5 at 1 hour to 32.5 at 24 hours. Both ARG and histopathological images clearly showed corresponding tumor regions with high T/N ratios. Nano-SPECT/CT detected a very clear tumor image from 4 hour...