肿瘤PET分子探针3-O-(2-~(18)F-氟乙基)-L-多巴的合成及初步生物学评价

正电子类氨基酸显像剂是~(18)F-氟代脱氧葡萄糖(~(18)F-Fluorodeoxyglucose,~(18)F-FDG)在临床肿瘤PET显像应用中的重要补充。针对6-~(18)F-氟-L-多巴(~(18)F-FDOPA)前体制备及标记过程的复杂性,本研究设计合成了一种新型~(18)F标记的氨基酸类肿瘤PET显像剂3-O-(2-~(18)F-氟乙基)-L-多巴(3-O-(2-~(18)Ffluoroethyl-L-DOPA,~(18)F-FEDOPA),并对其内生物分布及肿瘤PET显像进行了评价。以L-多巴(LDOPA)为原料经多步反应合成标记前体化合物N-叔丁氧羰基-(3-O-甲苯磺酸酯乙基-4-O-叔丁氧羰基)-L-多巴甲酯,通过~(18)F亲核取代反应实现放射性标记,经半制备高效液相色谱纯化、盐酸水解、NaOH中和后得到~(18)F-FEDOPA注射液。放化合成时间为90min,放化产率(33±6)%(n=10,衰减校正),放射性比活度为55GBq/μmol,放化纯度99%,4h后测定放化纯度95%,稳定性良好。小鼠体内生物分布表明,~(18)F-FEDOPA主要经肾脏代谢,心脏和脑组织摄取值较低,骨骼摄取随时间无明显变化。microPET/CT显像显示,~(18)F-FEDOPA在H22和S180肿瘤组织有明显摄取;与~(18)F-FDG相比,~(18)FFEDOPA在注射60min时肿瘤与心(或脑)的比值高。因此,~(18)F-FEDOPA有望成为一种新型氨基酸代谢类肿瘤PET显像剂。     

O-(3-~(18)F-氟代丙基)-L-酪氨酸的合成及其生物分布

采用两步法合成氨基酸代谢显像剂O-(3-^18F-氟代丙基)-L-酪氨酸(FPT)。首先，^18F^-与1，3-二对甲苯磺酸丙二酯(TsOCH2CH2CH2OTs)发生亲核氟化取代反应，生成3-^18F-1-对甲苯磺酸丙酯(^18F CH2CH2CH2OTs)；然后，^18FCH2CH2CH2OTs与L-酪氨酸二钠反应生成FPT。FPT总合成时间约为70min，未校正总放化产率为25％～30％，放化纯度大于95％。FPT在正常小鼠、肿瘤模型、炎症模型鼠体内的生物分布及荷瘤裸鼠PET显像结果表明：肾、肝、肺、血液等脏器放射性摄取较高，滞留时间较长，脑摄取放射性较低。FPT可被肿瘤细胞高摄取，而被炎症组织低摄取。给药后180min，荷瘤裸鼠PET显像清晰，肿瘤／肝脏放射性比值约为1．3。FPT制备简便，可以区分肿瘤和炎症，可望成为一种肿瘤氨基酸代谢PET显像剂。     

氟［18F］比他班自动化合成及初步临床应用

氟［¹⁸F］比他班（¹⁸F-florbetaben）是美国FDA于2014年批准上市的β-淀粉样蛋白显像剂,主要用于诊断阿尔茨海默病（AD）或其他认知障碍疾病。本研究使用改良后的国产氟多功能模块,建立¹⁸F-florbetaben自动化生产工艺,并针对其临床应用效果进行初步验证。结果显示,¹⁸F-florbetaben自动化合成耗时38 min,不校正合成效率为（45.0±2.3）%（n=6）,放化纯度大于95%,其临床PET显像效果理想。结果表明,国产氟多功能模块可实现¹⁸F-florbetaben的自动化生产,且工艺可靠,合成时间短。本文研究成果有助于推动该显像剂的国内临床使用。     

18F-硝基咪唑的放化稳定性

研究了乏氧显像剂¹⁸F-硝基咪唑（¹⁸F-FMISO）的全自动化合成方法,分析了影响¹⁸F-FMISO放化稳定性的因素。采用回旋加速器生产出来的¹⁸F^-,传输到住友CFN-MPS200合成装置中,经QMA柱捕获后淋洗到反应管,两次干燥除去水分,再与乙腈溶解的10 mg 1-（2’-硝基-1’-咪唑基）-2-氧-四氢呋喃基-3-氧-甲苯磺酰基-丙二醇（NITTP）进行亲核取代反应。反应液用盐酸水解后加缓冲溶液中和,进入制备型高效液相进行分离。流动相采用φ=15%的乙腈水溶液,流速3 mL/min,保留时间11 min。用旋转蒸发仪脱除溶剂,再用生理盐水溶解加入稳定剂得到18F-FMISO注射液。考察了不同活度、稳定剂、旋蒸温度对产品放化稳定性的影响,结果表明,不校正合成效率（EOS）为(45±5)%（n=20）,合成时间50 min,在抗坏血酸钠做为稳定剂的情况下,6 h后产品的放化纯度为95%;而抗坏血酸和乙醇不能在50 ℃以上作为稳定剂。¹⁸F-FMISO可以用CFN-MPS200合成模块全自动化合成,产品收率较高,工艺稳定,¹⁸F-FMISO在弱碱溶液中稳定性好,为肿瘤的乏氧显像提供了临床便利。     

Tau蛋白显像剂18F-THK5317的合成与初步临床应用

¹⁸F-THK5317是以tau为靶点的新型分子探针,本研究利用国产氟多功能模块自动化合成¹⁸F-THK5317,在动物实验基础上进行了初步的临床研究。以(S)-2-(4-甲氨基苯基)-6-［［2-(四氢吡喃基-)-3-对甲苯磺酰氧基］丙氧基］喹啉为前体,经亲核反应、酸水解、碱中和,分别采用混合液直接HPLC纯化与混合液经C18小柱预纯化后再HPLC分离纯化两种方法得到¹⁸F-THK5317;研究了药物在正常KM小鼠体内生物学分布;对比了¹⁸F-THK5317在正常人（HC）和阿尔茨海默病（AD）患者脑中PET/MR显像结果。先以C18小柱预纯化粗产品再用HPLC分离,能显著改善HPLC分离效果和提高产品放化纯度。¹⁸F-THK5317未校正合成产率为（18.7±5.3）%（n=7）,放化纯度大于95%。小鼠生物分布表明,探针易穿透血脑屏障,并且能迅速从正常脑组织清除,Brain_{1 min}/Brain_{60 min}放射性摄取比为34;PET/MR结果显示,AD患者双侧颞叶、皮层的放射性滞留均高于健康对照。以上结果表明,国产氟多功能模块能够稳定高效地合成符合药物质控标准的¹⁸F-THK5317,动物实验及初步临床研究表明¹⁸F-THK5317具有在体显像tau蛋白的潜力。     

68Ga标记成纤维细胞活化蛋白抑制剂的生物分布和胶质瘤模型micro-PET显像

为研究⁶⁸Ga标记的成纤维细胞活化蛋白抑制剂（⁶⁸Ga-FAPI-04）在正常小鼠和胶质瘤裸鼠模型体内的生物学分布及micro-PET显像,以DOTA修饰的成纤维活化蛋白抑制剂为前体合成⁶⁸Ga-FAPI-04。放射性HPLC测定其标记率,考察放化纯度及体外稳定性,通过测定⁶⁸Ga-FAPI-04脂水分配系数评估其水溶性。将20只ICR小鼠随机分为5组,尾静脉注射3.7 MBq ⁶⁸Ga-FAPI-04后5、15、30、60、120 min后处死并取出各脏器,称重并测定放射性计数,计算各组织器官的放射性摄取率。建立U87MG胶质瘤荷瘤鼠模型,进行生物分布及micro-PET显像研究。结果表明,⁶⁸Ga-FAPI-04的标记率为97.38%±1.32%（n=3）,放化纯度为100%,体外稳定性好,亲水性强。ICR正常小鼠生物分布实验显示,⁶⁸Ga-FAPI-04血液清除快,肾脏为主要排泄器官,脑部放射性摄取低。U87MG荷瘤裸鼠生物分布及micro-PET均显示肿瘤部位有较高的放射性摄取率,⁶⁸Ga-FAPI-04注射后90 min时肿瘤部位放射性摄取率达到（2.50±0.00）%ID/g。注射后30、60、90、120 min时,肿瘤与正常脑的肿瘤本底比(tumor-to-background ratio, TBR)分别为（6.26±0.09）、（5.06±0.02）、（5.54±1.47）、（5.51±0.03）。研究表明,⁶⁸Ga-FAPI-04制备简易方便、标记率高、体外稳定性好,主要通过肾脏排泄,在胶质肿瘤模型中具有较好的肿瘤靶向性,micro-PET显像清晰,是潜在的脑肿瘤显像剂。     

国产氟多功能模块合成雌激素受体显像剂16α-[18F]氟-17β-雌二醇

采用国产氟多功能模块,以3-甲氧基甲基-16,17-O-磺酰基-表雌三醇-O-环状砜（3-O-(Methoxymethyl) -16,17-O-sulfuryl-16-epiestriol,MMSE）为前体,在国产氟多功能合成模块的密封体系下,经¹⁸F标记合成雌激素受体显像剂16α-[¹⁸F]氟-17β-雌二醇（¹⁸F-FES）。结果显示：合成的¹⁸F-FES,不校正合成效率为8.2%,校正合成效率为12.8%;合成时间约为70 min,标记物¹⁸F-FES放化纯度大于98%,体外稳定性良好。以上结果表明,国产氟多功能模块可制备¹⁸F-FES溶液,制备的¹⁸F-FES溶液符合放射性药物的质量要求。     

18F标记非甾体类孕酮受体显像剂的制备

孕酮受体（PR）在乳腺癌中的水平可对乳腺癌的激素治疗进行预测和指导。5-［4-(3-氟丙基)-4-甲基-2-氧-1,4-二氢-2H-苯并［d］［1,3］口恶嗪-6-基］-1H-吡咯-2-甲腈（¹⁹FPr-Tanaproget）是Tanaproget的衍生物,它作为孕酮受体激动剂,对PR有高选择性和高亲和性,用放射性核素¹⁸F标记、正电子发射断层（PET）技术显像,可通过检测PR的情况,对乳腺癌进行诊断、治疗和预后评估。本实验以自制的氟标记前体,先合成了参比化合物¹⁹FPr-Tanaproget,再在氟多功能模块上合成了¹⁸FPr-Tanaproget,经Sep-Pak C-18柱和HPLC分离得到放化纯大于97%的产物。室温下在水中和血清中分别放置6h,放化纯仍大于95%。对标记率影响因素进行了优化,结果显示,最佳标记温度、时间、前体浓度分别为100℃、35min和32.7mmol/L,此条件下总的合成时间为45min,放化产率可达到10.9%（已校正）。     

肿瘤氨基酸代谢PET显像研究进展

氨基酸代谢PET显像在代谢分子显像中占有重要的地位。氨基酸PET药物可分为［1-¹¹C］氨基酸、标记α-碳位氨基酸、标记侧链氨基酸和N-取代标记氨基酸,肿瘤细胞摄取氨基酸PET药物机理主要涉及氨基酸转运。氨基酸代谢PET显像在神经精神疾病、脑瘤、神经内分泌肿瘤,以及其他多种肿瘤鉴别诊断方面具有优势。本文主要对肿瘤氨基酸代谢PET显像的研究进展进行了综述。     

18F-FLT的制备及其microPET显像

[摘要] 本文制备了增殖显像剂18F-FLT,考察其稳定性及研究其在肿瘤模型鼠的microPET显像。本文以3-N-t-叔丁氧羰基-1-[5’-O-(4,4’-二甲氧基三苯甲基)-2’-脱氧-3’-O-(4-硝基苯磺酰基-β-1)-苏戊呋喃糖]胸腺嘧啶脱氧核苷(N-BOC-FLT)为标记前体进行氟代亲核置换反应,用HPLC检测放射化学纯度（RCP）,进行稳定性研究和正常小鼠体内分布试验和肿瘤模型鼠microPET显像;研究结果 显示RCP〉95%,6h内稳定,正常小鼠体内分布显示,在60min时,肾,脾,肠摄取较多,心,肝,肺,膀胱摄取次之;肿瘤模型鼠microPET显像能够清晰地观察到接种部位的放射性浓聚。     

Preparation and Biological Evaluation of Novel 18F-labeled Phosphonuim Cation for Myocardial Perfusion Imaging with PET

In order to develop new PET myocardial perfusion imaging agent, a novel¹⁸F labeled phosphonium cation: (3-(［¹⁸F］fluoromethyl)benzyl) tris (2, 6-dimethoxyphenyl) phosphonium salt, ¹⁸F-2, had been designed and prepared. Biological evaluation of¹⁸F-2 had been performed in Kunming normal mice.¹⁸F-2 was obtained by a simple one-pot method and the radiochemical yield was (31±3)%. The total radio-synthesis time was less than 60 min and the radiochemical purity of final radiotracer was more than 95%. The biodistribution of¹⁸F-2 displayed a high heart uptake and good retention. The heart uptake of¹⁸F-2 at 5 and 60 min post-injection were (53.88±7.45)%ID/g and (23.93±3.28)%ID/g, respectively.¹⁸F-2 exhibited low radio-accumulation in non-target tissues and rapid clearance in liver, lung and blood. The heart to liver, heart to lungs and heart to blood ratio values were 3.99, 3.80 and 9.17, respectively. The results indicated that¹⁸F-2 could be as a promising myocardial perfusion imaging agent for PET imaging.     

Distribution of Dopamine D2 Receptor PET Imaging Agent 18F-Fallypride in the Brain of Normal and Aged Rats

With the progress of population aging, the incidence of age related disease has greatly increased. The dopamine D2 receptor is closely related to the age-related diseases, such as PD and AD. The PET imaging of the dopamine D2 receptor can provide noninvasive, dynamic, early and quantitative information on the function of the brain. So we intend to prepare dopamine D2 receptor PET imaging agent¹⁸F-Fallypride and to study the disturbution of the agent in the brain of normal and aged rats, further to explore the relationship between dopamine D2 receptor and senility.¹⁸F-Fallypride was prepared by nucleophilic reaction. And the PET image was performed in aged and normal rats 15 minutes after injection of the agent .Striatums were delineated as the region of interesting (ROI), the standard uptake value (SUV) of which was calculated. PMOD was used for image fusion ,partition and quantitative analysis of standard uptake values of each brain area. After imaging, cardiac ventricle was perfused. The brain was obtained and frozen. The contour structure was observed by HE staining.The results showed that the labeling yield was over 95% and the radiochemical purity was higher than 98%. The stability was still over 95% 2 hours after incubation with PBS. The striatum uptake of¹⁸F-Fallypride radioactivity in aged and normal rats 15 minutes after injection were (0.58±0.11)%ID/g, (0.39±0.14)%ID/g. The uptake of cortex cingulate, cortex insular, hypothalamus, olfactory, midbrain in normal rats ((0.120±0.012)%ID/g, (0.182±0.002)%ID/g, (0.111±0.002)%ID/g, (0.127±0.007)%ID/g, (0.083±0.012)%ID/g respectively) were inferior to aged rats ((0.154±0.013)%ID/g, （0.344±0.014）%ID/g, （0.244±0.019）%ID/g, （0.263±0.020）%ID/g, （0.216±0.012）%ID/g), which was displayed by PMOD. HE staining showed severe brain injury in elderly SD rats. Some neurons in the aged SD rats appeared acidophil change or nuclear fragmentation, accompanied by spongy deformation, lamellar or focal neuronal necrosis, and no obvious morphological changes. The relevance between dopamine D2 receptor and senility was demonstrated by PET imaging, which provided a basis for further research on the methodology of disease and pharmacodynamics research.     

新型Aβ斑块显像剂18F-W372

合成诊断阿尔茨海默病（Alzheimer’s disease,AD）的Aβ斑块显像剂：7-甲氧基-2(6-［¹⁸F］-氟-吡啶-3-基)咪唑［2,1-β］-8-吡啶噻唑（¹⁸F-W372）,不校正合成效率为（25.3±7.1）%（n=6）,产品放化纯大于99.5%,比活度为659~721PBq/mol。 ^{18F-W372小鼠体内分布实验显示,初始5min脑摄取为（4.36±1.44）%ID/g,清除较快,30min为（0.54±0.16）%ID/g,摄取比达到8,具有良好的生物学性能。急性毒性实验表明该药物安全可靠。在体试验显示药物注射40min,AD患者平均皮层/小脑吸收显著高于健康老年对照组。18F-W372是一种潜在的脑内Aβ淀粉显像剂。}     

Synthesis of 16-Epiestriol and its Radiolabeling Procedure

To explore novel synthetic routes of 16-epiestriol (Estra-1, 3, 5(10)-triene-3, 16β, 17β-triol), we used the estrone as the starting material. After some simple synthetic steps, 16-epiestriol was yielded. Identification and purity of intermediates in the synthetic routes were characterized by melting point and ¹H NMR spectrum analysis, respectively. In addition, the structure of 16-epiestriol was modified and radiolabeled with¹⁸F-fluoride to yield¹⁸F-FES. The corresponding quality control analysis of the injection were performed. The yield of two synthetic routes of 16-epiestriol were about 20% starting from estrone. Radiosynthesis of¹⁸F-FES was finished in 60 minutes with a radiochemical yield of (30±4)% and radiochemical purity greater than 99%. The¹⁸F-FES injection was colorless and clear and the pH value was 6.5-7.5. The specific activity of the injection saline was (1.75±0.25) Ci/μmol. In this study, 16-Epiestriol was yielded with a relatively high yield in two novel routes.¹⁸F-FES was finally yielded after structure modification of 16-epiestriol and the corresponding radiolabeling procudure. The quality control results of the¹⁸F-FES injection could meet the need in clinical examination.     

Automatic Synthesis of 18F-6-F-L-DOPA and its Application in Clinical PET Imaging

¹⁸F-6-Fluoride-L-DOPA (¹⁸F-DOPA) has an important value in the imaging diagnosis of neuroendocrine tumors. In this study, we used homemade Fluoride-module to synthesis¹⁸F-DOPA and evaluate its clinical imaging.¹⁸F-DOPA was synthesized by direct nucleophilic reaction with 6-boric acid-dimethoxy-L-DOPA as precursor, Cu(OTf)₂(py)₄ as catalyst, and hydrolysis by hydriodic acid. Quality control and the in vitro stability were preformed. The¹⁸F-DOPA was confirmed PET imaging of neuroendocrine neoplasms and control. It took 60 minutes from ¹⁸F ions to ¹⁸F-DOPA, no corrected efficiency was （10.0±2.3）% (n=6), radiochemistry purity was over 99%. It could got 7.4 GBq of¹⁸F-DOPA once time. The trace of ascorbic acid or ethanol could prevent radiolysis of ¹⁸F-DOPA. The striatum was seen at¹⁸F DOPA imaging. The radioactivity were mainly extracted through kidney and urine. A positive lesion in pancreatic in patient with neuroendocrine tumor.¹⁸F-DOPA was synthesized by direct nucleophilic reaction with homemade Fluoride-module. It could got good repeatability and high quality for clinical used.     

Full Automated Synthesis of18F-FDOPA and Preliminary PET/CT Imaging

¹⁸F-fluoro-L-dihydroxyphenylalanine (¹⁸F-FDOPA) as a dopamine neurotransmitter imaging agent has been widely used for diagnosis and therapy evaluation of Parkinson's disease, brain tumors and neuroendocrine diseases with positron emission tomography (PET) imaging in clinical setting and research. To meet the increasing clinical demand in oncology and neurology, a routine protocol for the automated synthesis of¹⁸F-FDOPA with a disposable cassette system on an imported multifunctional synthesizer was studied and discussed.¹⁸F-FDOPA was automatically synthesized via a multiple-step reaction, including fluorination, reduction, iodization alkylation and hydrolysis, following purification by using a semi-preparative high-performance liquid chromatography (HPLC) system which was built in the multifunctional synthesizer. After HPLC purification, the purified¹⁸F-FDOPA solution was collected and passed through a sterilizing filter into a collection bottle. The final¹⁸F-FDOPA injection was obtained for quality control (QC) determination. The QC indexes of the final products were detected： the injection was colorless and transparent, pH value was at 4 to 5.5, radiochemical purity >98%, radionuclide purity >99%, specific activity >1.9 GBq/μmol, K_2.2.2 content <50 mg/L, methanol content <0.01%, alcohol content <0.01%, dichloromethane content <0.01 mg/L, dimethylformamide content <15 mg/L, bacterial endotoxin test <0.100 EU/mL, sterility test 0 cfu/mL,and abnormal toxicity test was negative. PET/CT imaging of rats was performed by intravenous injection of¹⁸F-FDOPA half an hour after the intraperitoneal injection of carbidopa, PET/CT scan was performed after 100 min post-injection. The imaging of¹⁸F-FDOPA showed symmetry high uptake in the bilateral striatum of normal rats. The decay-corrected radiochemical yield of¹⁸F-FDOPA from the¹⁸F-fluoride was (63.1±3.8)% (n=10) at the end of synthesis (EOS), the radiochemical purity was no less than 98%, and the total radiosynthesis time was within 80 min. The quality control results demonstrated that the quality indexes of the final injection solution met the relevant requirements of radiopharmaceutlcals, which were well-suited for clinical application. An efficient and high reproducible automatic method for the radiosynthesis of¹⁸F-FDOPA with high radiochemical yields and good radiochemical purity is obtained and performed via a multi-step reaction on the multifunctional synthesizer.¹⁸F-FDOPA can be used for animal and human PET imaging.     

国产FDG模块半自动合成~(18)F-氟乙基胆碱

18F-氟乙基胆碱(18F-FECH)是18F-FDG的重要补充,在脑瘤转移和前列腺癌及转移的诊断方面有重要的应用价值。利用国产单次PET-FDG-TI-I CPCU型FDG合成模块,未改变硬件,通过更改试剂与耗材,半自动合成18F-FECH,并在产品收集瓶前增加C18纯化柱,减少K2.2.2杂质的含量。合成时间约30min,放化产率42.0%(未时间校正,n=5),放置6h后放化纯度99.0%,体外稳定性良好;合成时间和产率与国内外模块结果相近。结果表明,在国产单次PET-FDG-TI-I CPCU型FDG模块上可半自动合成18F-FECH,合成效率及放化纯度较高。     

Optimization of the Radiosynthesis of the Dopamine Transporter Imaging Agent of11C-β-CFT

The optimization for high synthesis yield was designed with ¹¹C-Triflate-CH₃I as methylation agent for dopamine transporter imaging agent of¹¹C-β-CFT. The influence factors of the synthesis process were discussed, and the optimum synthetic conditions were established. In the paper, the study showed that the amount of precursor, the irradiation time, eluated condition, the reaction solvent etc could effect the synthetic efficiency.¹¹C-β-CFT was automatic synthesized on PET-CM-3H-IT-Ⅰ with the optimum process conditions as the irradiation time 10-24 minutes, 0.5-1.0 g/L of precursor in 0.2 mL acetone: acetonitrile(1∶1, V∶V) and room temperature. We obtained a radiochemical yield of (76.93±6.49)% (n=76,¹¹C-Triflate-CH₃ EOB). The radiochemical purity of final products were over 97%. The specific activities of final products were over （56.26±1.55） TBq/g. It took 16 minutes from¹¹C-CO₂ to¹¹C-β-CFT and the radio activity of¹¹C-β-CFT were (8.07±1.94) GBq (n=76). By optimization of the technological conditions, the target product was suitable for clinical, the synthetic process was reliable and full automated, the product yield was improved and the residual problem of Sep-Pak C18 was resloved.