Radiolabeling of Nanoshells with Cu-64 and In-111 for PET and SPECT Imaging in Rats
H. Xie, Z. Wang, A. Bao, B. Goins, W.T. Phillips, C.L. Coleman
Texas Southern University, US
Keywords: nanoshells, radiolabeling, Cu-64, In-111, PET, SPECT, imaging, cancer
Abstract:Here we report for the first time the radioactive labeling of gold-silica nanoshells with Cu-64 and In-111. A bifunctional polyethylene glycol (PEG2000) is used as crosslinker to connect nanoshells with DOTA or DTPA, which are chelating agents for Cu-64 and In-111respectively. By using Cu-64 for PET/CT imaging and In-111 for SPECT/CT imaging, we monitored the in vivo distribution of Cu64-nanoshells and In111-nanoshells in nude rats with a head and neck squamous cell carcinoma (HNSCC) xenograft. Blood samples were collected at various time points post intravenous injection and the blood clearance of Cu64-nanoshells and In111-nanoshells was determined in terms of radioactive counts. PET and SPECT images of the rats showed that both Cu-64 and In-111 appeared to be useful for tracking the in vivo distribution of nanoshells and both agents appeared to accumulate in the tumor. Overall image quality appeared better with Cu-64 labeling than with In-111 labeling. Therefore, Cu-64 could be a better choice for the tracking of nanoshells in future studies. In summary, this study shows a successful method of conjugating radioactive agents to nanoshells and in vitro and in vivo results support the application of nanoshells for pre-clinical live imaging by using the radioactive agent, Cu-64.