Objective: Radioactive gold nanoparticles (R-GNPs) simultaneous emitting beta particles and gamma rays provide the niche for killing tumor cells and tracking 198Au-GNP in vivo. The aim of this study is to assess the eficacy of 198Au-GNP treatment in both of subcutaneous xenograft and orthotopic animal models.Methods: Radioactive gold nanoparticles could be prepared from aqueous Au(III) in one-step using nuclear reactor. In xenograft, the mice bearing tumor around ~ 00 mm3 were treated radioactive gold nanoparticles to observe tumor suppression. In orthotopic model, tumor volume was estimated using microPET/CT by intravenous injection of FDG. The animals bearing tumor size over 3 mm in each dimension were treated by 198Au-GNPs through intracranial injection. The fold changes of tumor volume were compared by PET images.Results: In xenograft model, the radioactive gold nanoparticles showed very good eficacy to dramatically suppress tumor growth; however, onradioactive gold nanoparticles did not show any perceivable effect. In orthotopic model, the maximum survival of control group (n=8) was β1 days (0% of survival rate) after tumor cell implantation whereas animals treated with 198Au-GNPs (n=8) showed 87.5% survival rate at the same day. Tumor volumes between the control and treated groups were signiicantly different (p