Automatic radiolabeling of the norepinephrine transporter targeted tracer 18F-mFBG and evaluation of 18F-mFBG PET/CT imaging in pheochromocytoma / 中华核医学与分子影像杂志

ABSTRACT

Objective:To fulfill the automatic radiolabeling of the norepinephrine transporter (NET) trancer 18F-meta-fluorobenzylguanidine (mFBG), and explore the 18F-mFBG PET/CT imaging effect of pheochromocytoma. Methods:On the basis of the chemical structure of mFBG, a spirocyclic iodonium ylide was used as the precursor to undergo a 3-step reaction sequence (radiofluorination, deprotection and neutralization) on AllinOne synthesis module. Purification by high performance liquid chromatography and formulation were conducted to generate 18F-mFBG. The corresponding quality control tests of 18F-mFBG product was performed. Afterwards, a postoperative patient with pheochromocytoma underwent 18F-mFBG PET/CT imaging. Results:The radiosynthesis was accomplished within 70 min, and 18F-mFBG was obtained in (17.8±2.4)% non-decay-corrected radiochemical yield ( n=5), with radiochemical purity >97% and molar activity >59.2 GBq/μmol. Sterility test, bacterial endotoxins test, abnormal toxicity test and the acetonitrile residue all met the requirements of Pharmacopoeia of the People′ s Republic of China (2020 Volume Ⅳ). The 18F-mFBG PET/CT imaging disclosed high uptake in pheochromocytoma and clear localization of lesions. Conclusions:The automatic radiolabeling of the NET targeted tracer 18F-mFBG is successfully realized by commercially available synthesis module, and the production quality meets all requirements for clinical translation. 18F-mFBG has a potential to image neuroendocrine lesions in clinical setting.