ABSTRACT
Objective:To investigate the radiation dosimetry and biodistribution of 68Ga-FAPI-04 PET/CT in patients with hepatobiliary tumor. Methods:A total of six patients with hepatic lesions who underwent PET/CT examination in Peking Union Medical College Hospital were enrolled. After intravenous injection of radiotracer 68Ga-FAPI-04 at (170.57 ± 14.43) MBq, whole-body imaging were performed at the time points of 3, 10, 15, 20, 30 and 60 min, respectively. Biodistribution pattern was observed. Regions of interest were manually delineated. Radiation dosimetry of all target organs were calculated by Olinda/EXM software. Results:The radioactive uptake dissipated gradually in liver whereas it was relatively stable in tumor lesions. The average SUV max of tumor lesions reached the maximum value (13.87± 2.55) at 20 min after injection. The target-to-background ratio increased with time, reaching the maximum value (10.09 ± 8.17) at 30 min after injection. The average effective dose in total body was (0.020 ± 0.002) mSv/MBq and organ with the highest effective dose was bladder wall at (0.146 ± 0.035) mSv/MBq. Conclusions:The effective dose in total body of 68Ga-FAPI-04 was similar to that of 18F-FDG. 68Ga-FAPI-04 is expected to be a PET/CT radiotracer for hepatobiliary tumors in consideration of rapid tumor uptake, low accumulation of liver background, and no influence of blood sugar levels.
ABSTRACT
Objective:To prepare 68Ga-fibroblast activation protein inhibitor (FAPI)-04, and evaluate its biodistribution and imaging characteristics in animals and healthy volunteers, in order to investigate the clinical translation potential. Methods:68Ga-FAPI-04 was synthesized by a manual method and its radiolabeling yield, radiochemical purity, and stability ( in vivo and in vitro) were analyzed. ICR mice ( n=16) were scarified at 5, 30, 60 and 120 min postinjection of 68Ga-FAPI-04 (1.11 MBq) to measure radioactive counts in main organs. The dynamic mircoPET imaging was acquired for 60 min on 3 ICR mice, and tumor imaging capabilities were examined with nude mice bearing HepG2 tumors. Furthermore, 2 healthy volunteers (1 male with age of 64 years, 1 female with age of 56 years) were recruited for the investigation of probe biodistribution in humans. A serial whole-body dynamic PET/CT scan was performed immediately following injection. Results:68Ga-FAPI-04 was synthesized within 20 min with the radiochemical yield of (68.7±4.0)% (decay corrected). The radiochemical purities of 68Ga-FAPI-04 were over 99% and the products were stable for 180 min in vitro and for 90 min in blood. 68Ga-FAPI-04 was mainly cleared through urinary tracts, while other organs only showed mild tracer accumulation. MicroPET imaging showed high uptake of 68Ga-FAPI-04 in the tumor tissue of mice, and the ratio of tumor/liver was 2.14±0.01 (35 min). The PET/CT imaging results of healthy volunteers revealed 68Ga-FAPI-04 could be quickly cleared. Conclusion:68Ga-FAPI-04 has many advantages for PET imaging, such as easy labeling, good stability, quick clearance and low background signals in the liver, which can be used as an attractive PET tracer for detection hepatocellular carcinoma.
ABSTRACT
Objective To synthesize 4 kinds of 111 In?TPP cations and evaluate their properties as tumor cationic radiotracers in vivo and in vitro. Methods DO3A?xy?TPP, DO3A?xy?mTPP, DO3A?xy?dmTPP and DO3A?xy?tmTPP were radiolabeled with 111 In;their lipid?water partition coefficients and in vivo and in vitro stability were evaluated. The binding affinities of 4 kinds of 111 In?radiotracers were determined in cell uptake and cell efflux assay using U87MG tumor cells. Biodistribution studies and γ imaging studies were performed using the athymic nude mice bearing U87MG human glioma xenografts to explore the biologi?cal properties of 4 kinds of 111 In?radiotracers. One?way analysis of variance was used. Results The labeling yields of 4 kinds of 111 In?radiotracers were all above 85%, and the radiochemical purity were all greater than 99% after purification. Binding assay in U87MG cells showed that 4 kinds of radiotracers had great binding affinity and cell retention ability, and 111In?DO3A?xy?mTPP had the best binding ratio (1?49%;F=177.8, P<0.05) . Gamma imaging and biodistribution results showed that the U87MG tumors could be clearly visualized by 111In?DO3A?xy?mTPP, 111In?DO3A?xy?dmTPP and 111In?DO3A?xy?tmTPP, and the liver uptake of the 3 tracers was lower than that of 111In?DO3A?xy?TPP. In particular, 111In?DO3A?xy?mTPP had the best tumor/liver ratio (0.13±0.05, 2 h postinjection;F=9.4, P<0?05). Conclusions The tumor?targeted ability of 111In?DO3A?xy?mTPP is better than those of 111In?DO3A?xy?dmTPP, 111In?DO3A?xy?tmTPP and 111In?DO3A?xy?TPP, suggesting that it has the potential to be a promising tumor cationic radiotracer.