ABSTRACT
Objective:To automatically synthesize Al 18F-1, 4, 7-triazacyclononane-1, 4, 7-triacetic acid (NOTA)-fibroblast activation protein inhibitor (FAPI)-04, perform PET/CT imaging in vivo, and evaluate its diagnostic efficacy on tumors. Methods:Al 18F-NOTA-FAPI-04 was produced in All-in-one automatic synthesis module and its quality control was conducted by high performance liquid chromatography (HPLC) equipped with a radioactive detector. Al 18F-NOTA-FAPI-04 PET/CT imaging was performed in normal BALB/c mice ( n=3) and 4T1 breast cancer models ( n=3) to determine its biodistribution. Then Al 18F-NOTA-FAPI-04 and 18F-FDG PET/CT imaging were performed in a hepatocellular carcinoma patient (male, 51 years old). Results:The synthesis time of Al 18F-NOTA-FAPI-04 was about 35 min, and the radiochemical yield was (25.2±1.9)% (attenuation correction, n=3). The product was colorless transparent solution with pH value of 7.0-7.5, and the specific activity was (46.11±3.07) GBq/μmol (attenuation correction, n=3). The radiochemical purity was above 99.0% and was still above 98.0% at room temperature after 6 h. PET/CT imaging in mice showed that physiological uptake of Al 18F-NOTA-FAPI-04 was mainly in biliary system and bladder, and Al 18F-NOTA-FAPI-04 highly concentrated in tumor xenografts. PET/CT imaging in the patient showed that Al 18F-NOTA-FAPI-04 obtained high tumor background ratio (TBR) values of 4.1, 8.9, 5.4, 4.8, 2.2 in parasternal lymph nodes, anterior diaphragmatic lymph nodes, hilar lymph nodes, pancreaticoduodenal ligament lymph nodes, abdominal aortic lymph nodes, respectively, while TBR values were 1.0, 2.8, 5.0, 2.1, 1.1 by 18F-FDG. Conclusions:Al 18F-NOTA-FAPI-04 can be synthesized with short time, high radiochemical yield and good stability using All-in-one module. Al 18F-NOTA-FAPI-04 PET/CT imaging has high contrast and excellent diagnostic efficacy on tumors.