Abstract
PurposeIn this study, a novel Al18F-NOTA-FAPI probe was developed for fibroblast activation protein (FAP) targeted tumour imaging, which was available to achieve curie level radioactivity by automatic synthesizer. The tumour detection efficacy of Al18F-NOTA-FAPI was further validated both in preclinical and clinical translational studies. MethodsThe radiolabeling procedure of Al18F-NOTA-FAPI was optimized. Cell uptake and competitive binding assay were completed with U87MG and A549 cell lines, to evaluate the affinity and specificity of Al18F-NOTA-FAPI probe. The biodistribution, pharmacokinetics, radiation dosimetry and tumour imaging efficacy of Al18F-NOTA-FAPI probe were researched with healthy Kunming (KM) and/or U87MG model mice. After the approval of ethical committee, Al18F-NOTA-FAPI probe was translated into clinical for the PET/CT imaging of first 10 cancer patients. ResultsThe radiolabeling yield of Al18F-NOTA-FAPI was 33.8 ± 3.2% through manually operation (n = 10), with the radiochemical purity over than 99% and the specific activity of 9.3-55.5 MBq/nmol. Whole body effective dose of Al18F-NOTA-FAPI was estimated to be 1.24E-02 mSv/MBq, lower than several other FAPI probes ( 68Ga-FAPI-04, 68Ga-FAPI-46 and 68Ga-FAPI-74). In U87MG tumour bearing mice, Al18F-NOTA-FAPI showed good tumor detection efficacy from the results of micro PET/CT imaging and biodistribution studies. In organ biodistribution study of human patients, Al18F-NOTA-FAPI showed lower SUVmean than 2-[18F]FDG in most organs, especially in liver (1.1 ± 0.2 vs. 2.0 ± 0.9), brain (0.1 ± 0.0 vs. 5.9 ± 1.3), and bone marrow (0.9 ± 0.1 vs. 1.7 ± 0.4). Meanwhile, Al18F-NOTA-FAPI do not show extensive bone uptakes, and was able to find out more tumour lesions than 2-[18F]FDG in the PET/CT imaging of several patients. ConclusionAl18F-NOTA-FAPI probe was successfully fabricated and applied in fibroblast activation protein targeted tumour PET/CT imaging, which showed excellent imaging quality and tumour detection efficacy in U87MG tumour bearing mice as well as in human cancer patients.
Clinical Translational Evaluation of Al18F-NOTA-FAPI for Fibroblast Activation Protein Targeted Tumour Imaging