Novel PET kit for 18F-AlF-NOTA-PRGD2 and pilot study in human patients

1452 Objectives 18F-labeled RGD peptides, such as 18F-galacto-RGD, 18F-AH11185 and 18F-FPPRGD2, have been translated into clinic for cancer research. However, wide-spread use of these tracers is limited by the multi-step and laborious radiosynthesis procedures. The aim of this study was to develop a facile kit formula for our recently developed novel PET probe 18F-AlF-NOTA-PRGD2 (18F-AlF-NOTA-PEG3- E[c(RGDyK)]2) and evaluate the feasibility of this RGD peptide tracer for clinical use. Methods To optimize the kit, the effects of pH, Al3+/NOTA-PRGD2 ratio, amount of activity for reaction and volume of 18F, different co-solvents, reaction time and temperature were examined. The kit was radiolabeled in one step by adding F-18 solution, heating briefly, and then purified by C18 Sep-Pak cartridge. The protocol was approved by the institutional review board and written informed consent was obtained from all participants.Two patients (one man with suspected lung cancer and one woman with scrofula) were recruited for 18F-AlF-NOTA-PRGD2 PET/CT imaging. Results An optimized kit containing 16 nmol of NOTA-PRGD2 and 12 nmol of AlCl3 was labeled with F-18, heated to 100°C briefly and then purified by SPE to produce 18F-AlF-NOTA-PRGD2. The total time was about 20 min. A 1:2 ratio of F-18 in saline to ethanol and pH at 3.5 ± 0.5 were optimal for radiolabeling with reasonable yield (~30%) and high specific activity (> 30 GBq/ µmol). 18F-AlF-NOTA-PRGD2 showed predominant renal clearance. In the lung cancer patient, a large lesion in the right lung was clearly demarcated by PET/CT. Some small metastatic lesions in the bone can also be seen (Fig. 1). On the other hand, despite of FDG uptake in the mesenteric lymph nodes, 18F-AlF-NOTA-PRGD2 was negative in the scrofula patient (Fig. 2). Conclusions We have developed a facile kit for rapid synthesis of 18F-AlF-NOTA-PRGD2 in high yield and specific activity for clinical use. Pilot studies in human patients suggest that this RGD peptide tracer is promising for cancer imaging. Research Support NSFC(811711399, 81028009), RC2011095, and NIBIB IRP