[en] ¹⁸F-DCFPyL, a PSMA-based PET imaging agent for prostate cancer, was auto-synthesized and evaluated. Following the direct nucleophilic heteroaromatic substitution with [¹⁸F] fluoride at the ortho-position of precursor, the deprotection of the ester moieties of the intermediate with different acids was attempted to obtain a good hydrolysis yield. The biodistribution in normal NIH mice and PET/CT imaging for a patient with biochemical recurrence of prostate cancer were also performed. The results showed that no remarkable discrepancy of the hydrolysis efficiency was found among three kinds of acids, H₃P0₄, HC1 and HI, which were 17.1%, 16.9% and 18.4%, respectively with a specific activity of 54 to 90 GBq/pμmol. The highest levels of radioactivity in the NIH mice were observed in the kidneys. Meanwhile, the uptake of the tracer in the blood was declined rapidly and a low accumulation of the radio-tracer was observed in most of the other organs. ¹⁸F-DCFPyL PET imaging for a postoperative patient with biochemical recurrence of prostate cancer can detect small metastatic foci that can not be detected by the CT. ¹⁸F DCFPyL was synthesized reliably and repeatedly by domestic synthesis module and it passed the quality control. It has satisfactory properties in vivo and is probably suitable for early diagnosis of prostate cancer and detection of lesions in patients with biochemical recurrence of prostate cancer. (authors)

[en] To study the stability of "1"8F-FDG with routinely synthesis at high radio-dose and high radioconcentration, "1"8F-FDG was added 0.1% ethanol or repurification by solid-phase extract ion for radiolytic "1"8F-FDG to improve its radiochemical purity (RCP). The results showed that the RCP declined from 99% to 95% within 4 h at 6 TBq/L for room temperature (RT). The radiolysis could be depressed with 0.1% ethanol, the RCP could be over 95% even if the radioactivity concentration was 7.4 TBq/L at RT for 6 h. The repurification method could improve the RCP of "1"8F-FDG from 80% to 99%. Micro PET/ CT imagings of normal rats showed that the vertebra had high uptake with radiolytic "1"8F-FDG because of impurity. There were no radioactivity uptaking in bone with repuification of "1"8F- FDG. It indicated that 0.1% ethanol could be used as stabilizers for "1"8F-FDG to improve the RCP when "1"8F-FDG had high radio-do se and high radioconcentrtion. The radiolytic 18 F-FDG could be repurified by so lid-phase extraction to remove the radio-impurity. The method of added 0.1% thanot could be combined with repurification method to assure the RCP of "1"8F-FDG for over 95% at any given time andradiodose or contcentrayion. (authors)

[en] The residual solvents in PET radiopharmaceuticals were analyzed by GC, which were acetonitrile, ethanol, N, N-dimethylethanolamine (DMEA), dimethylsulfoxide (DMSO). The standard curves were established with the AT-624 capillary column at GC, and the sensitivity of acetonitrile and ethanol were 0.004-0.320 g/L and 0.010-0.120 g/L respectively. The residual solvents of acetonitrile, ethanol, DMEA and DMSO in PET radio- pharmaceuticals were analyzed by GC. The linearity were 0.9994, 0.9999, 0.9997, 0.999 6 respectively. The residual of acetonitrile were (0.0313±0.0433), (0.0829±0.0668), (0.0156±0.0059), (0.0254±0.0266) g/L in "1"8F-FDG, "1"8F-FLT, "1"1C-CFT, "1"1C-PIB respectively. The residual of ethanol was (0.0505±0.00528) g/L in "1"8F-FDG. The residual of DMSO were (0.0331±0.0180) g/L, (0.0238±0.0100) g/L in "1"8F-W372 and "1"1C-DTBZ respectively. The residual of DMEA was (0.0348±0.0022) g/L in "1"1C-Choline. The survived of organic solvent in PET radiopharmaceuticals can be analyzed with GC directly. The results showed that the QC should be done in PET radiopharmaceuticals purity with semi-HPLC to avoid the high residual. (authors)

[en] A new Aβ-Amyloid Imaging agent 7-Methoxy-2 (6-fluoropyridin-3-yl) imidazo [2, 1-b]-8-pyridinothiazol (¹⁸F- W372) was synthesized, the undecay corrected radiochemical yield was 20±n% (n= 3), the radiochemical purity was more than 99.5%, and the specific activity was 19.5 Ci/μmol. Biodistribution of the ¹⁸F-W372 in mice indicates that uptake was high in brain, the brain ID%/g was 4.36±1.44% at 5 min, the washout from normal brain was fast, and the brain ID%/g was 0.54±0.16%/g. At 30 min The acute toxicity test of ¹⁸F-W372 proved it was safely for clinical used. The cortical/cerebellar SUVR was higher in AD patients than controls after injection of ¹⁸F-W372 of 40 min. The result showed that ¹⁸F-W372 is a excellent imaging agent for Aβ-Amyloid. (authors)

[en] A high-performance liquid chromatography-tandem mass spectrometric method (LC/MS/MS) was used to quantify Kryptofix 2. 2. 2 (K_2.2.2) in ¹⁸F-FDG and ¹⁸F-FLT and other ¹⁸F-radiopharmaceuticals. First molecular ion peak m/z 377.4 [M+H]⁺ were detected by full scan mode, then the daughter ions 114.1, 289.4 and 333.5 m/z were detected by product ion scan mode, the mass scanning mode was set to multiple reaction monitoring (MRM) and programmed to monitor the transitions of the parent/daughter ion pairs of 377.4/114.1, 377.4/289.4 and 377.4/333.5 m/z for K_2.2.2. The calibration curve was established over the range of 20 ∼ 500 μg/L, the linear correlation coefficient was 0.9999, the limit of quantitation for K_2.2.2 was 20 μg/L. Reproducibility and accuracy all accorded with expectation. Direct measurement of the concentration of K_2.2.2 in the routine radiopharmaceutical of ¹⁸F-Fag was less than 20 μg/L, and the concentration of K_2.2.2 in 5 bat chs ¹⁸F- Felt products were between 0.286 and 16.9 mg/L. Above all, Lc/Ms/Ms is the most sensitive method for the quantification of K_2.2.2 so far. (authors)

[en] Objectives: Automatic synthesis of ¹¹C-DANB as a serotonin imaging agent was established and Micro PET/CT imaging with Wistar rat was performed. Methods: Optimization of ¹¹C-DASB synthesis was established by modifying different ¹¹C-methylation agents, solvent and reaction conditions. Automated procedure for the synthesis of ¹¹C-DASB was established, and Micro PET/CT imaging was complied with Wistar rat. Results: The optimized ¹¹C-DASB synthesis was obtained. When ¹¹C-CH₃-Triflate was used as methylation agent, 500 μL DMSO was used to dissolve 1 mg precursor, the reaction was carried out at 80 ℃ for 2 min, the radiochemical synthesis yield was 63.7%. Micro PET/CT studies in rat showed that the initial uptake of ¹¹C-DASB in the brain was high, especially in region of the highest density of SERT, such as colliculus and mid brain. Conclusion. The study should provide the basis for routine preparations of ¹¹C-DASB with high reliability, it may be useful for PET imaging of SERT binding sites in the brain. (authors)

[en] ¹¹C-MET was synthesized by the solid phase reaction of ¹¹CH₃I and precursor L-homocysteine, and the radiochemical purity of ¹¹C-MET was analyzed by HPLC, ¹¹C-methanol and ¹¹C-methyl iodide were prepared and analyzed, respectively. The primary impurity of the product were analyzed. The influence on the quality of product was investigated by changing the concentration of sodium hydroxide solution and the solvent of dissolving precursor. The results showed that ¹¹C-MET with higher yield and good radiochemical purity would obtain by using 0.1 mL 2 mol/L NaOH to dissolve the precursor, then injecting it into the C18 column after blending 0.1 mL ethanol. (authors)

[en] A new Aβ-amyloid imaging agent 7-methoxy-2 (6-fluoropyridin-3-yl) imidazo [2, 1-b]-8-pyridinothiazol (¹⁸F-W372) is synthesized, the non-decay corrected radiochemical yield is (25.3 ± 7.1)% (n = 6), the radiochemical purity is more than 99.5%, and the specific activity is 659-721 PBq/mol. Biodistribution of the ¹⁸F-W372 in mice indicates that uptake is high in brain, the brain is (4.36 ± 1.44)%ID/g at 5 min, the washout from normal brain is fast, and the brain is (0.54 ± 0.16)%ID/g at 30 rain post injection. The acute toxicity test of ¹⁸F-W372 proves its safety in clinical use. The cortical/cerebellar specific uptake is higher in AD patients than in controls at 40 rain after injection of ¹⁸F-W372. ¹⁸F-W372 may have potential as a Aβ-amyloid imaging agent for Alzheimer's disease. (authors)

[en] 3'-Deoxy-3'-[¹⁸F] fluorothymidine (¹⁸F-FLT) is a radiotracer for the imaging of tumor proliferation. A clinically applicable automatic system for the preparation of ¹⁸F-FLT was developed by modifying a domestic ¹⁸F-FDG synthesizer with semipreparative HPLC. Fifteen milligrams of 3-N-Boc-5'-O-dimethoxytrityl-3'-O-nosyl-thymidine were dissolved in 0.5 mL DMSO and reacted with dried ¹⁸F-fluoride at 100 ℃ for 5 min. The obtained material was hydrolyzed with 1 mol/L HCl at 110 ℃ for 5 min, and then neutralized with 2 mol/ L NaOH before HPLC purification was performed. The desired radioactive fraction was collected after passing through a 0.22 m filter into a 30 mL vial as the final product. The ¹⁸F- FLT labelling yield was found to be 67.5% (n=8) by the radio-TLC method, and 39.4% (n=6) by the HPLC method. The yield as the final product for clinical use was 21.2% (n=3, not corrected for decay). The total preparation time, including the time for HPLC purification, was 30 min. The radiochemical purity of the final product was over 99%, and the specific activity was higher than 740 TBq/mg (180 PBq/mol). The final product was stable for more than 6 h in the 10% alcohol solution. This preparation system with semi-preparative HPLC enables us to produce ¹⁸F-FLT with a stable yield for clinical use. (authors)

[en] Abstract: Automatic synthesis of ¹¹C-Raclopride was used for routinely clinical imaging with home-made C-11 synthesized module. METHODS: ¹¹C-Triflate-CH₃ was bubbled through a vial at room temperature, containing a acetone solution of precursor and NaOH. The reaction solution was transferred to Semi-HPLC for purification. The crude production was purified by C-18 Solid-Extraction-Purification (SEP). The injection solution was formatted by 1 mL alcohol eluated from the SEP-C-18, the eluated soluation was diluted with saline to less 10% of alcohol. RESULTE: The amount of base leaded to increase the yields of by-production of C-N methlyation. The synthesis yield was (55.1 ± 8.4)% (n = 40) with precursor of 0.1 to 0.4 mg, and had no relationship with NaOH in 1 μmol to 50 μmol. It took 28 min from ¹¹CO₂ to obtain ¹¹C-Raclopride injection solution. The radiochemical purity was over 99%. The radiochemical concentration was 370 to 550 MBq/mL at specific activity of 1.73 × 10¹⁴ Bq/g. The injection solution was proved to be sterile and pyrogen free. CONCLUSION: ¹¹C-Raclopride was automatic synthesized from ¹¹CH₃-Triflate with home-made C-11 synthesizer module. The quality and quantity of ¹¹C-Raclopride injection solution was confirmed to be suitable for clinical PET imaging. (authors)