Simple Synthesis of [18F] AV-45 and its Clinical Application in the Diagnosis of Alzheimer's Disease.

OBJECTIVE: [18F] AV-45 can be produced in a simple, stable, and repeatable manner on the Tracerlab FXF-N platform using a self-editing synthetic procedure and solid-phase extraction purification method. This technique is applied to positron emission tomography (PET) imaging of Alzheimer's disease (AD) to observe its distribution and characteristics in various brain regions and its diagnostic efficiency for the disease. METHODS: The precursor was subjected to nucleophilic radiofluorination at 120°C in anhydrous dimethyl sulfoxide, followed by acid hydrolysis of the protecting groups. The neutralized reaction mixture was purified by solid phase extraction to obtain a relatively pure [18F] AV-45 product with a high specific activity. A total of 10 participants who were diagnosed with Alzheimer's disease (AD group) and 10 healthy controls (HC group) were included retrospectively. All of them underwent [18F] AV-45 brain PET/CT imaging. The distribution of [18F] AV-45 in the AD group was analyzed visually and semi-quantitatively. RESULTS: Six consecutive radiochemical syntheses were performed in this experiment. The average production time of [18F] AV-45 was 52 minutes, the radiochemical yield was 14.2 % ± 2.7% (n = 6), and the radiochemical purity was greater than 95%. When used with PET/CT imaging, the results of the visual analysis indicated increased [18F] AV-45 radioactivity uptake in the frontal, temporal, and parietal lobes in AD patients. Semiquantitative analysis showed the highest diagnostic efficacy in the posterior cingulate gyrus compared with other brain regions (P < 0.001). CONCLUSION: Intravenous [18F] AV-45 was successfully prepared on the Tracerlab FXF-N platform by solid-phase extraction of crude product and automated radiochemical synthesis. PET/CT imaging can be used to diagnose and evaluate AD patients and provide a more robust basis for clinicians to diagnose AD.

Evaluation of 18F-FDG PET/CT myocardial metabolism image quality / 中国医师杂志

Objective:To evaluate the value of 18F-fluorodeoxyglucose positron emission computed tomography ( 18F-FDG PET/CT) myocardial metabolic image quality by the ratio of the maximum standard uptake value (M/B) of left ventricular myocardium to cardiac blood pool. Methods:The clinical data of 145 non diabetes patients with coronary heart disease who were admitted to the First Affiliated Hospital of Xinjiang Medical University from January 2016 to August 2022 were retrospectively selected. All patients received intravenous injection of 18F-FDG for myocardial glucose metabolism imaging. According to the visual (qualitative) analysis, the image was divided into three categories: the best, the second best and the worst. Group A was the best image quality group, while Group B was the second best and the worst image quality group. The left ventricular myocardium, cardiac blood pool and descending aorta were semi-quantitatively analyzed, and M/B was calculated. Results:All 145 patients underwent image fusion analysis. Image visual (qualitative) analysis showed that the myocardial metabolic image quality of 111 patients was evaluated as the best (111 patients in Group A), 19 patients as the second best, and 15 patients as the worst (34 patients in Group B). The SUVmax value of the descending aorta in the two groups was lower than that of the left ventricle, with statistically significant difference (all P<0.05). The M/B value of group A was higher than that of group B, with statistically significant difference ( P<0.05). Conclusions:For the evaluation of image quality and the reliability of image interpretation, M/B value may be a good evaluation index, which reduces the interference of image quality evaluation due to high 18F-FDG uptake in some heart blood pools (background), and improves the accuracy of evaluation of myocardial viability.

Optimization of Automatic Synthesis and Separation of [18F] AV-45 and Quality Control.

Objective: Based on the Tracerlab FXF-N platform, a synthesis program and preparative high-performance liquid chromatography (HPLC) purification program edited by us can stably and repeatedly produce [18F] AV-45 without changing the process. The [18F] AV-45 produced meets the main indexes of radiopharmaceutical intravenous preparations. Methods: The O-toluene sulfonated precursor (1 mg) was subjected to nucleophilic radiofluorination at 115°C in anhydrous dimethyl sulfoxide (DMSO), then the protective group was hydrolyzed by acid. The neutralized reaction mixture was purified through a preparative HPLC then formulated for injection using a C18 purification cartridge. This method yielded a relatively pure [18F] AV-45 product with high specific activity. Results: Four consecutive radiochemical synthesis operations were carried out in this experiment; the average production time of [18F] AV-45 preparation was 60 min, the radiochemical yield was 14.8 ± 2.1% (n = 4), the radiochemical purity was greater than 95%, and the other important quality control indexes met the requirements of radioactive drugs for intravenous administration. Conclusion: This experiment was based on the Tracerlab FXF-N platform with the synthesis program and preparative HPLC purification program edited by us. Through screening and optimization of the separation and purification system and the separation and analysis system, as well as automatic radiochemical synthesis and preparation quality control, intravenous [18F] AV-45 was successfully prepared.