A Dual Reporter Iodinated Labeling Reagent for Cancer Positron Emission Tomography Imaging and Fluorescence-guided Surgery.

The combination of early diagnosis and complete surgical resection offers the greatest prospect of curative cancer treatment. An iodine-124/fluorescein-based dual-modality labeling reagent, I-124-Green, constitutes a generic tool for one-step installation of a positron emission tomography (PET) and a fluorescent reporter to any cancer specific antibody. The resulting antibody conjugate would allow both cancer PET imaging and intraoperative fluorescence -guided surgery. I-124-Green was synthesized in excellent radiochemical yields of 92 +/- 5% (n = 4) determined by HPLC with an improved one-pot three-component radioiodination reaction. The A5B7 carcinoembryonic antigen (CEA)-specific antibody was conjugated to I-124-Green. High tumor uptake of the dual-labeled A5B7 of 20.21 +/- 2.70, 13.31 +/- 0.73, and 10.64 +/- 1.86%ID/g was observed in CEA-expressing SW1222 xenograft mouse model (n = 3) at 24, 48, and 72 h post intravenous injection, respectively. The xenografts were clearly visualized by both PET/CT and ex vivo fluorescence imaging. These encouraging results warrant the further translational development of I-124-Green for cancer PET imaging and fluorescence-guided surgery.