该项目获得了NIH / NIBIB 1K99EB020075授予Pedro Brugarolas奖，以及芝加哥创新交易所创新基金奖给Brian Popko和Pedro Brugarolas。布莱恩·波波科教授非常感谢他对该项目的指导和财务支持。芝加哥大学教授陈小铎教授和芝加哥大学综合小动物成像研究资源，慷慨分享了实验室空间和设备。 IBA被公认为赞助本文的开放获取。

小心:涉及使用放射性物质的所有程序必须经当地的辐射安全办公室批准。当使用放射性物质时，穿上实验室外套和个人辐射徽章。随时使用两层手套，并在涉及处理放射性的每个步骤之后检查盖革计数器。如果手套被放射性废物污染并更换外套手套。使用适当的屏蔽，最小化与辐射源接触的时间并最大化距离。 1.实验前一周:材料的制备<ol><li>下载[ 18 F] 3F4AP序列:Synthera用户可以登录用户数据库（http://www.iba-radiopharmasolutions.com/products/chemistry）并下载3F4AP的序列文件。其他合成器的用户可能需要根据步骤顺序编写自己的脚本。浏览通过注释的序列来熟悉s涉及合成的。脚。 </li><li>确保有足够的气体用于合成。合成器需要压缩气体，氦气或氮气。它还需要&gt; 75 psi的压缩空气。确保压力在制造商推荐的范围内。 </li><li>制备HPLC流动相:制备1μL50mM磷酸钠和10mM三乙胺。使用pH计，通过在搅拌下滴加饱和氢氧化钠将pH调节至8.0±0.1。通过0.22μm瓶盖过滤器过滤溶液并加入5％体积的乙醇。 </li><li>干燥的玻璃器皿在烤箱过夜。 </li></ol> 2.实验日:氟-18到达之前<ol><li> 使用1 mL注射器，用合适的试剂填充试剂瓶。对于小瓶2和3，使用保持在氩气下的烘箱干燥的小瓶和无水溶剂。用压接机用压接密封条密封小瓶。 <ol><li>填充样品瓶1（直径11毫米/ 2毫升体积）al）与400μLTBA-HCO 3 +800μL乙腈（MeCN）。 </li><li>向样品瓶2（13mm / 4mL）中加入50μL前体溶液1.0mg / mL +450μLMeCN。 </li><li>用500μL的MeCN填充样品瓶3（11mm / 2mL小瓶）。 </li><li>用4mL 0.2％草酸的甲醇（MeOH）填充小瓶4（13mm / 4mL小瓶）。 </li></ol></li><li>调节QMA（强阴离子交换）和氧化铝-N固相萃取柱。使用10mL注射器，通过QMA逐渐通过5 mL 8.4％NaHCO 3，然后通过5 mL超纯水去离子型I水（25℃时为18.2MΩ•cm）。通过5mL超纯水通过氧化铝-N柱，然后加入5mL MeOH + 0.2％草酸。 </li><li>打开HPLC，并用流动相每分钟4 mL处理C-18柱30分钟。 </li><li>将新的催化剂筒装载到氢化器盒架上，开始流速为0.5mL / min的100％MeOH。小号并将氢调节器调节至50 psi，并将墨盒调节15分钟（ 图2 ）。 </li><li>通过在其位置上引入小瓶1至4组装集成流体处理器（IFP）， 如图3所示连接墨盒和收集瓶。将带有通气针的收集瓶连接到氢化器的输出管线。 </li><li>启动合成器的软件。输入登录名和密码。根据制造商的说明对合成器执行预运行检查。 </li><li>单击"序列"，然后单击"打开"加载3F4AP序列。 </li><li>通过单击屏幕上的"加载"按钮加载IFP。键入运行的文件名，然后单击"开始"启动序列。 （自动合成器将在18 F加载步骤之前自动暂停。） </li><li>作为合成器观看，通过例行自检步骤（序列的第一部分）。看看scree以确保没有警告或警报。当合成器冲洗线路并预热反应容器以准备运行时，注意声音。温度指示器应上升并保持在65℃。等待信号（听觉蜂鸣声），指示合成器准备好进行18 F传输。 </li></ol>实验日: 18 F标签<ol><li>将所需回旋加速器产生的18 F量从回旋加速器靶转移到18 F小瓶。验证放射性的量，并记录它与传送时间。 注意:如果不使用直接管线进行18 F-转运，请使用带有针头的预充式注射器将活动通过隔膜转移到小瓶。起始放射性的量取决于辐射安全办公室设定的限值和所需量的最终示踪剂。典型数值介于50和500 mCi之间。 </li><li&gt;按"恢复"恢复合成器上的序列。这将启动将18F转入QMA。 </li><li> 在计算机屏幕上的整个自动序列中监视合成的进度。 <ol><li>观察将18 F从小瓶转移到QMA上90秒。捕获18 F -在QMA上，用TBA-HCO 3溶液（小瓶1）洗脱。 （序列的第二部分） </li><li>在TBA 18 F在减压（5 kPa）和加热（100ºC）下干燥，然后进行额外的干燥和冷却步骤，监测合成仪上的压力和温度曲线。 （序列的第3部分） </li><li>观察无水MeCN（小瓶3）和前体溶液（小瓶2）的转移到反应器中，以及它如何在室温下反应1分钟。溶液应为无色或微黄色。 （序列的第4部分） </li><li>观察草酸的转移溶液（小瓶4）。观察，因为溶液是从反应器通过氧化铝-N柱转移到最终产品小瓶的压力。 （序列的第5部分） </li></ol></li><li>在序列结束时，打印报告，弹出IFP，关闭气罐，并关闭软件。 </li><li>在首次建立该程序时，通过将药筒和小瓶单独引入剂量校准器来测量氧化铝-N盒和收集瓶中的放射性。记录测量的活动和时间。将用过的墨盒放在有铅废物容器中。将收集瓶放入一个屏蔽的容器中，以便运输到下一步。 </li><li>使用连接有2"针的1 mL注射器，手动将大约100μL中间产物溶液样品转移到标准HPLC样品瓶中进行质量控制。将10μL此样品注入HPLC，以评估纯度和中间件的身份二酸酯化合物。 注意:HPLC条件:XDB 5μm，9.4 x 250 mm C18色谱柱。流量4 mL / min。流动相（50mM Na 2 HPO 4，10mM TEA，5％EtOH）。等度15分钟</li></ol> 4.实验日:氢化注意:将产品注入氢化器必须使用适当的屏蔽预防措施进行。氢气必须正确处理和排气。 注意:氢化反应器可以连接代替合成仪上的HPLC色谱柱，并使用合成仪软件进行控制。 <ol><li> 通过开始合成器HPLC序列，以0.5mL / min设置氢化器流。手动设置氢气压力至50 psi。 <ol><li>完成标记和淬火步骤后，合成仪将中间产物溶液转移到氢化器/ HPLC循环中。 </li></ol></li><li>当HPL上出现放射性峰时C软件切换收集阀以收集产品。使用剂量校准器测量粗产品的放射性。 注意:粗产物应注入热电池内的自动化HPLC系统。纯化后，然后收集最终产品，并按照USP和FDA规定将其分配到无菌ISO 5级层流气流热池中。 </li></ol> 5.实验日:剂量的净化和制备<ol><li>将粗产物注入HPLC中，并使用自动级分收集器收集对应于最终产物峰的级分。每个管含有0.66mL溶液。 注意:HPLC条件:XDB 5μm，9.4 x 250 mm C18色谱柱。流量4 mL / min。流动相（50mM Na 2 HPO 4，10mM TEA，5％EtOH）。等度15分钟收集4-15分钟。 </li><li>使用剂量校准器测量每个部分的放射性并进行记录。组合最高量的分数的放射性（通常为管14-18）。 </li><li>用10 mL注射器抽取产品溶液，并将样品通过0.22μm过滤器送入无菌瓶中。在小瓶标签上记录放射性的量，合成时间结束和溶液体积。这是注射的最终剂量。放置〜0.8 mL溶液进行质量控制测试。 </li></ol> 6.实验日:质量控制（QC）测试<ol><li> 剂量释放前: 通过铅屏蔽玻璃检查剂量。溶液必须清澈，无色，无颗粒物。 </li><li> 放射化学特征: <ol><li>对于RadioTLC:使用参考标准并列在TLC板上的一滴样品。使用95％MeOH:5％乙酸在TLC室上运行TLC板。在UV照明下可视化参考标准，并用铅笔标记其位置。 </li><li>将TLC板粘贴到radioTLC扫描的阶段呃记录时间的高峰。参考标准和放射性峰值的R f值必须在5％以内。 </li><li>对于RadioHPLC:在HPLC上运行10μL具有和不具有参考标准的剂量。参考标准和放射性峰值的保留时间必须匹配。必须在加标样品上看到单一的coelution峰。 </li></ol></li><li>放射化学纯度:测量放射HLCLC和radioTLC靶峰的曲线面积。所有放射性峰值组合面积的面积必须&gt; 95％。 </li><li>对于特定的放射性:使用预先建立的校准曲线，计算特定放射性，作为峰值放射性的量（在步骤5.2中测量）超过由UV HPLC曲线曲线下的面积确定的质量。比放射性必须高于50mCi /μmol。 </li><li>对于残留溶剂分析:测量剩余溶剂的量ts（MeCN，MeOH），使用气相色谱法。乙腈溶剂的含量必须&lt;0.04％，甲醇的溶剂浓度必须&lt;3,000 ppm。 EtOH的量必须小于10％w / v。 </li><li>对于无菌过滤器完整性测试（泡点）:将步骤5.3中使用的过滤器连接到配有压力调节器的氮气供给器，并将针浸入水中。在观察压力表时逐渐打开气阀。过滤器应承受高达50 psi的压力，不会出现爆裂，如针缺少气泡流所证明的。增加压力超过50psi直到气流从针头出来。记录这个压力，它是爆破压力，它必须&gt; 50 psi。 </li><li>对于放射性核素半衰期:在剂量校准器间隔≥10分钟的两个时间点测量产品的放射性。使用下面的等式计算半衰期。半衰期必须在18分钟内达到5分钟以内（10分钟）9±5分钟）: t½计算 = 0.693 t÷ln（A 1 / A 2 ） 其中t是测量之间的间隔，A 1 ，A 2是在每个时间点测量的活度。 </li><li>对于放射性核素的同一性和纯度:使用γ计数器获得产物样品的γ射线谱。光谱应在511 keV的能量下显示一个单一的光峰。光谱中应该没有其他的光谱峰。 </li><li>对于内毒素分析:使用LAL显色内毒素定量试验测量内毒素水平。对于最终产品体积为10 mL的1:10稀释产物，内毒素含量必须&lt;1.75 EU / mL。 </li><li>记录每个QC测试的结果。释放动物研究的剂量，只有所有的测试通过。 </li><li>剂后释放: 对于无菌试验:将两个流体的巯基乙酸和胰蛋白酶的剂量样品加入大豆肉汤14天后，媒体上看不到增长。 </li></ol> 7.实验日期:计算（表1） <ol><li>对于非衰变校正放射化学产率（ndc RCY）:计算ndc RCY作为最终产物中放射性的量超过起始放射性。 </li><li>对于放射性标记效率:计算标签收率，作为收集小瓶中放射性与氧化铝​​-N盒（非法定的[ 18 F] F - ））和收集瓶中放射性的比值。 </li><li>对于氢化产率:计算加氢产率，作为注入HPLC的放射性的所需峰的放射性量。 </li><li>对于过滤损失:计算滤波损失，因为过滤前过滤器和注射器中的放射性比放射性残留。 </li></ol>

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</ol>

作者没有什么可以披露的。

PET示踪剂的制备需要有效的标签，用最少的用户干预来最小化辐射暴露14 。在这里，我们描述了目前正在研究的成像脱髓鞘的PET示踪剂[ 18 F] 3F4AP的放射化学合成的第一个半自动化程序。这种半自动化方法产生具有高纯度和足够的比活性的放射性示踪剂，用于动物研究。用于合成该化合物的先前方法依赖于手工合成6 ，其显着限制了可产生的放射性示踪剂的量。具有合成自动化方法还提供更多的可重复产量，并且使得更容易将程序转移到具有相似设备的其他实验室。未来完全自动化程序的努力将有助于大量用于大型动物或人类的研究的示踪剂的生产。 18 F的亲核交换18 F将放射性同位素纳入感兴趣的分子。该反应的优点是其快速且几乎仅产生所需的产物，而不需要执行潜在的冗长的纯化步骤以除去过量的前体。使用氟化物交换标记反应（如这里使用的氟化物交换标记反应）的一个局限性在于，由于冷化合物的初始质量，定义为mCi中的放射性量的量的最终比活性与以μmol计的化合物量相比有限。在我们的标准条件下，从100-200mCi的18F-和50μg前体开始，合成结束时的典型比活性高达100-200mCi /μmol，这似乎足以用于临床前PET成像研究。然而，比活性可以通过增加18F- </su同时保持质量低。已经有几个报道，通过以高活性和低前体量15,16开始，以高比活性（1-3Ci /μmol）通过氟化物交换生产放射性配体。 与PET示踪剂的所有放射化学合成一样，为了最小化放射性衰变，关键是快速工作。尽量减少处理放射性物质的时间，使用适当的屏蔽，并最大限度地发挥放射性物质与使用者之间的距离，使辐射暴露最小化也是重要的。这些方面在协议的下半年（净化和质量控制）尤其重要，其中用户必须手动将溶液注入HPLC，收集级分并过滤最终产品。 与PET示踪剂的所有放射化学合成一样，为了快速工作至关重要推动放射性衰变。尽量减少处理放射性物质的时间，使用适当的屏蔽，并最大限度地发挥放射性物质与使用者之间的距离，使辐射暴露最小化也是重要的。这些方面在协议的下半年（氢化和纯化）期间特别重要，其中用户必须手动将溶液注入氢化器中，收集级分，设置干燥程序，将产物重新溶解在缓冲液中并过滤。在过滤步骤中，很容易在小瓶的壁中失去大量的放射性物质。因此，重要的是在过滤之前尝试收集所有的液体。使用更大量的缓冲液以溶解可以提高回收率，但不鼓励使用它，因为它将需要在HPLC上注入更大的体积，导致峰扩大并增加最终剂量的体积。 为了排除故障最优化程序对于跟踪每个步骤的收益率很重要。对于大多数步骤，可以简单地通过测量任何步骤之前和之后的放射性量来完成。在反应的情况下，可以通过定量HPLC峰来计算产率。结果部分中的表1显示了每个步骤的典型收益率。下面的表2列出了许多常见的故障，潜在的故障原因和如何纠正它们。 最后，即使这里展示的程序是合成[ 18 F] 3F4AP的具体步骤，一般工作流程和许多个别步骤对其他化合物17的合成是常见的。在本文中，我们还展示了对任何PET示踪剂进行的典型QC测试。

在人体内非侵入性地追踪小分子药物的能力对精密医学具有很大的潜力。在分子成像技术中，正电子发射断层扫描（PET）具有许多有利的特征:PET检测器的高灵敏度允许检测和量化非常少量的放射性物质，并且扫描仪的特征允许药物定位的精确空间映射1,2 ， 3 。例如，PET允许基于放射性葡萄糖类似物[ 18 F] FDG 4的摄取水平检测和定位肿瘤和转移。 PET还可以提供特定脑受体的定位和定量，以及它们对于诊断和理解神经和精神疾病有用的占有率。为了发展一个小分子的PET示踪剂，目标化合物必须用正电子发射同位素标记，通常为11 C或18 F.在这两种放射性同位素之间， 18 F具有较长的半衰期（109分钟，对于11 C为20.3秒） ，允许多剂量和异地生产。然而，向分子加入18 F可能是具有挑战性的。 18 F标记需要快速反应，与自动化相容，减轻化学家直接处理活性并接收高吸收辐射剂量。 我们最近描述了使用吡啶N-氧化物作为吡啶氟化的前体，以及在[ 18 F] 3F4AP 6的放射化学合成中使用该化学物质，FDA批准的用于多发性硬化的药物的放射性氟化类似物，4-氨基吡啶（4AP） 7,8,9 。钍目前正在研究新型放射性示踪剂作为脱模髓鞘的PET示踪剂10,11,12。在本视频文章中，我们使用IBA Synthera合成单元（以下称为"合成仪"）和内部制造的流化氢装置展示了该化合物的半自动化合成。合成基于图1所示的反应。准备工作约需1小时，放射性标签和纯化1.5小时，质量控制程序0.5小时。

<table><tbody><tr><td>Cyclotron produced [&lt;sup&gt;18&lt;/sup&gt;F]fluoride</td><td>House supplied/Zevacor</td><td>IBA Cyclone 18</td><td>100-200 mCi</td></tr><tr><td>Integrated fluid processor for production FLT/FDG</td><td>ABX</td><td>K-2715SYN</td><td>Cassette used for nucleophilic substitution</td></tr><tr><td>Anhydrous acetonitrile</td><td>Janssen</td><td>36431-0010</td><td>Transfer under nitrogen</td></tr><tr><td>Methanol</td><td>Janssen</td><td>67-56-1</td><td></td></tr><tr><td>ultrapure water</td><td>house supplied</td><td></td><td>Millipore MilliQ system</td></tr><tr><td>TBA-HCO3</td><td>ABX</td><td>808.0000.6</td><td>abx.de</td></tr><tr><td>QMA</td><td>Waters</td><td>WAT023525</td><td>Quaternary methyl ammonium: Anion exchange solid phase extraction cartridge for trap and release of &lt;sup&gt;18&lt;/sup&gt;F&lt;sup&gt;-&lt;/sup&gt; from the target water</td></tr><tr><td>Sodium bicarbonate</td><td>ABX</td><td>K-28XX.03</td><td>Prefilled 5 mL syringes</td></tr><tr><td>Alumina-N</td><td>Waters</td><td>WAT020510</td><td>Alumina-N solid phase extraction cartridge (for trapping unreacted &lt;sup&gt;18&lt;/sup&gt;F&lt;sup&gt;-&lt;/sup&gt;)</td></tr><tr><td>3-fluoro-4-nitropyridine N-oxide</td><td>Synthonix</td><td>76954-0</td><td>Store in desicator. Precursor</td></tr><tr><td>3-fluoro-4-aminopyridine</td><td>Sigma Aldrich</td><td>704490-1G</td><td>Reference standard</td></tr><tr><td>Oxalic acid</td><td>Sigma Aldrich</td><td>75688-50G</td><td></td></tr><tr><td>Sodium phosphate monobasic</td><td>Fisher Scientific&amp;nbsp;</td><td>S80191-1</td><td></td></tr><tr><td>Triethyl amine</td><td>Fisher Scientific&amp;nbsp;</td><td>04885-1</td><td></td></tr><tr><td>Ethanol</td><td>Decon Labs</td><td>DSP-MD.43</td><td>USP</td></tr><tr><td>Final product vial</td><td>ABX</td><td>K28XX.04</td><td></td></tr><tr><td>Millex Filter Syringe</td><td>Millex</td><td>SLGVR04NL</td><td></td></tr><tr><td>10% Pd/C cartridge</td><td>Sigma Aldrich</td><td>THS-01111-12EA</td><td></td></tr><tr><td>11 mm vials + crimp seals</td><td>Fisher Scientific&amp;nbsp;</td><td>03-250-618, 06-451-117, or equivalent</td><td></td></tr><tr><td>13 mm vials + crimp seals</td><td>Fisher Scientific</td><td>06-718-992, 06-718-643, or equivalent</td><td></td></tr><tr><td>HPLC vials</td><td>Fisher Scientific</td><td>03-391-16, 03-391-17, or equivalent</td><td></td></tr><tr><td>SEMIPREP C18 column</td><td>Agilent</td><td>990967-202</td><td></td></tr><tr><td>V-vials</td><td>Alltech</td><td></td><td></td></tr><tr><td>Syringes: 1, 3, 10 mL</td><td>Fisher Scientific</td><td>14-829-10D, 14-829-13Q, 14-829-18G, or equivalent</td><td></td></tr><tr><td>Compressed gases: N&lt;sub&gt;2&lt;/sub&gt;, He, H&lt;sub&gt;2&lt;/sub&gt;</td><td>Airgas</td><td>UHP N300, UHP HE300, UHP H300, or equivalent</td><td></td></tr><tr><td>TLC plates</td><td>Sigma Aldrich</td><td>Z193275, or equivalent</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Synthera automated synthesizer</td><td>IBA SA, Belgium, iba-worldwide.com</td><td>Synthera, 250.001</td><td>Automatic synthesis unit</td></tr><tr><td>In-house hydrogenator</td><td>See picture</td><td></td><td>See text description</td></tr><tr><td>Hot cells</td><td>Comecer</td><td></td><td>For manipulating radioactive materials</td></tr><tr><td>RadioTLC scanner</td><td>Eckert and Ziegler</td><td></td><td>For handling sterile materials</td></tr><tr><td>HPLC</td><td>Dionex</td><td>Ultimate 3000</td><td></td></tr><tr><td>Dose calibrator</td><td>Capintec</td><td>CRC15</td><td>Or equivalent</td></tr><tr><td>Gamma counter</td><td>Capintec, 7 Vreeland Road, Florham Park, NJ 07932</td><td>CRC 15, PET-CRC25, or equivalent</td><td>For measuring radioactivity</td></tr><tr><td>Personal dosimeters</td><td>Packard</td><td>Cobra II</td><td>For measuring gamma spectrum</td></tr><tr><td>Personal radiation badges and rings</td><td>Atlantic Nuclear</td><td>Rados Rad-60 Electronic Dosimeter, or equivalent</td><td></td></tr><tr><td>Rotavap + vacuum pump</td><td>Landauer</td><td></td><td></td></tr><tr><td>Lead pigs + syringe shields</td><td>Heidolph</td><td></td><td>Or equivalent</td></tr><tr><td>Geiger counter</td><td>Pinestar</td><td></td><td></td></tr><tr><td>Geiger counter</td><td>Ludlum</td><td>Model 3 + Pancake GM detector, 4801605, 47-1539, or equivalent</td><td></td></tr></tbody></table>

automated radiochemical synthesis of [18f]3f4ap: a novel pet tracer for imaging demyelinating diseases

3- [ 18 F]氟-4-氨基吡啶[ 18 F] 3 F4AP是经FDA批准的多发性硬化4-氨基吡啶（4AP）药物的放射性氟化类似物。该化合物目前正在研究中作为用于脱髓鞘的PET示踪剂。我们最近描述了一种新的化学反应，以生产由吡啶N-氧化物的直接氟化组成的五氟化吡啶以及该反应用于[ 18 F] 3 F4AP的放射化学合成。在本文中，我们演示如何使用自动化合成器和内部制造的流化氢反应器来生产该示踪剂。我们还展示了在释放用于临床前动物成像研究的放射性示踪剂之前执行的标准质量控制程序。这种半自动化程序可以作为未来生产[ 18 F] 3F4AP进行临床研究的基础。

[ 18 F] 3F4AP的放射化学合成包括两个步骤（ 图1 ）。第一步使用合成单元以完全自动化的方式进行（ 图3 ）。这种基于盒式的系统使用四个试剂瓶和一个反应器小瓶，并具有计算机控制的阀，其允许试剂的转移和混合以及加热，加压和排空反应器。此外，它还支持用于分离试剂的标准固相萃取柱。计算机界面允许用户编写和修改脚本，以便运行自己的综合。在[ 18 F] 3F4AP的情况下，合成程序由五个基本部分组成。在第一部分中，合成器执行自检步骤，预热反应堆，并等待操作人员18 F准备就绪的信号。在第二部分，[ 18 F]氟化物被转移将18 F小瓶插入阴离子交换柱中，并使用四丁基碳酸氢铵溶液从柱中洗脱到反应器中。第三部分，合成仪在真空下共沸干燥[ 18 F]氟化物，使其对亲核取代反应。在第四部分中，前体被自动加入到反应器中，其与18F-反应产生标记的化合物。最后，通过在甲醇中加入0.2％草酸猝灭反应，这防止了产物的碱促进的分解，并且最终的溶液在通过氧化铝 - N型药筒后被压力转移到收集瓶中未反应的氟化物。 标签步骤完成后，可以取小样品进行质量控制。在HPLC上运行样品提供了标签步骤的确认和估计放射化学纯度（ 图4 ）。此外，从HPLC上的UV迹线可以使用预先建立的校准曲线来计算产物的质量。 当进行中的质量控制HPLC运行时，进行第二反应步骤，还原N-氧化物和硝基。为了做到这一点，基于Yoswathananont 等人发表的方法，将标记的产物自动注入内部加氢装置。 13 （ 图2 ）。该装置包括一个HPLC泵和一个压缩氢罐，通过装有止回阀的管线与流化氢装置连接，以防止回流。产物由HPLC泵推动，并与T型混合器中的氢混合。然后将该混合物在固体支持物上通过含有10％Pd / C催化剂的小筒。通过cata之后然后以小部分收集还原产物。 氢化后，将粗产物输送并手动注入HPLC以纯化最终产物（ 图5 ）。已选择HPLC的流动相与动物注射相容。然后收集与产物相对应的峰，并过滤灭菌以获得最终剂量。 在释放PET成像研究的剂量之前，进行质量控制测试。执行这些测试以确保示踪剂是其应该是化学实体，并且它对于注射是安全的。这些测试中的一些可能不需要注射到动物体内，但通常建议遵循人体使用指南。这样做确保了产品的质量，从而增加了对结果的信心，并大大提高了产品质量揭示未来向人类注射产品制造过渡。 表1包含典型的合成参数，包括初始量放射性，前体的初始量，每个步骤的产率，比活性，过滤损失等。这些参数有助于故障排除和未来的优化过程。 <img alt="图1" src="/files/ftp_upload/55537/55537fig1.jpg" /> 图1.反应方案放射化学合成由19 F / 18 F交换标记，然后进行钯催化氢化。 <a href="http://ecsource.jove.com/files/ftp_upload/55537/55537fig1large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图2"<html> / src ="/ files / ftp_upload / 55537 / 55537fig2.jpg"/&gt; 图2.加氢系统。设备原理图该设备基于Yoswathananont 等人的出版物（参考文献13）。 <img alt="图3" src="/files/ftp_upload/55537/55537fig3.jpg" /> 合成器集成流体处理器（IFP）和试剂方案。 IFP包含四个试剂瓶，一个QMA盒和一个反应瓶。 <a href="http://ecsource.jove.com/files/ftp_upload/55537/55537fig3large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <img alt="图4" src="/files/ftp_upload/55537/55537fig4.jpg" /> 图4.用于中间产品的UV和radioHPLC示踪剂。 3-氟-4-硝基吡啶N-氧化物在313nm具有特征吸收。e.jove.com/files/ftp_upload/55537/55537fig4large.jpg"target ="_ blank"&gt;请点击此处查看此图的较大版本。 <img alt="图5" src="/files/ftp_upload/55537/55537fig5.jpg" /> 图5.用于最终产品的UV和radioHPLC示踪剂。 3-氟-4-氨基吡啶在254nm吸收。 <a href="http://ecsource.jove.com/files/ftp_upload/55537/55537fig5large.jpg" target="_blank">请点击此处查看此图的较大版本。</a> <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 概念 </td><td> 平均值（n = 4） </td><td> SD </td><td> 注释 </td></tr><tr><td>初始18 F活动（mCi） </td><td> 148.0 </td><td> 44.9 </td><td>合成开始</td></tr><tr><td>前体用量（μg） </td><td> 50 </tD&gt; <td></td><td>使用50μL1.0 mg / mL原料</td></tr><tr><td>在QMA（mCi）中剩下的活动</td><td> 3.0 </td><td> 1.7 </td><td>在标签步骤结束时测量</td></tr><tr><td>放射性标记产率</td><td> 29.7％ </td><td> 6.3％ </td><td> Act_collection_vial÷（Act_collection_vial + Act_AluN） </td></tr><tr><td>放射化学纯度（HPLC-1） </td><td> &gt; 98％ </td><td></td><td>从HPLC-1 QC </td></tr><tr><td>规格。法案。中间体（mCi /μmol） </td><td> 122.9 </td><td> 29.7 </td><td>从HPLC-1使用校准曲线</td></tr><tr><td>加氢回收（直流） </td><td> 74％ </td><td> 9.0％ </td><td>修正为朽烂</td></tr><tr><td> HPLC放射化学纯度（HPLC-2） </td><td> 90.7％ </td><td> 2.9％ </td><td>由HPLC-2计算</td></tr><tr><td>干燥效率</td><td> &gt; 98％ </td><td></td><td>修正为朽烂</td></tr><tr><td>过滤恢复</td><td> 93.5％ </td><td> 1.7％ </td><td>修正为朽烂</td></tr><tr><td>剂量（mL） </td><td> 3.3 </td><td></td><td>收集具有最高放射性的级分</td></tr><tr><td> 规格。法案。最终产品（mCi /μmol） </td><td> 75.5 </td><td> 30.0 </td><td>从HPLC-3使用校准曲线</td></tr><tr><td> 综合效率 </td><td> 8.5％ </td><td> 3.6％ </td><td>非衰变校正</td></tr><tr><td> 合成时间（min） </td><td> 104 </td><td> 11.2 </td><td></td></tr></tbody></table> 表1.放射化学合成参数。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 常见问题 </td><td> 潜在的原因和解决方案 </td></tr><tr><td rowspan="3"> [ 18 F]氟化物不能从QMA有效地洗脱出来</td><td> ·TBA-HCO 3未正确准备。确保浓度足够。 </td></tr><tr><td> ·TBA-HCO 3小瓶有泄漏。在将其安装在IFP上之前，确保压接密封很紧，并且隔膜未被刺穿。 </td></tr><tr><td> ·TBA-HCO 3状况不佳。订购新批次。 </td></tr><tr><td rowspan="2">标签产量低</td><td> ·前体溶液中有水分。干燥前体和溶剂。 </td></tr><tr><td> ·温度过低</td></tr><tr><td rowspan="3">反应溶液为黄色</td><td> ·产品由于底层而分解。少用TBA-HCO 3 。 </td></tr><tr><td> ·有t太多的前兆少用前体。 </td></tr><tr><td> · 18 F - 的溶剂溶剂少。使用更多的溶剂。 </td></tr><tr><td> radioHPLC上的额外峰值</td><td> ·硝基取代基:降低反应温度或缩短反应时间。 </td></tr><tr><td rowspan="3">氢化反应不起作用</td><td> ·催化剂不好使用新的墨盒。 </td></tr><tr><td> ·流速太快，催化剂和基材之间不能充分接触。减少流量</td></tr><tr><td> ·氢气压力过低增加H 2压力。 </td></tr><tr><td>氢气压力在程序中显着增加</td><td> ·墨盒的完整性受到损害，坚实的支持阻塞了线路。停止流动并关闭气体。让放射性衰减。取出催化剂筒并冲洗系统。放一个碳粉盒</td></tr><tr><td>加氢收率低</td><td> ·与催化剂（MeCN，草酸）竞争的杂质太多。减少杂质量或增加前体质量（警告:增加前体量会降低比活度）。 </td></tr><tr><td rowspan="2">从氢化步骤回收放射性较低</td><td> ·系统有泄漏。检查泄漏和反冲入氢气管线。 </td></tr><tr><td> ·化合物在反应器中脱氟。评估不同的反应条件（压力，温度，流量等 ）。 </td></tr><tr><td rowspan="2">过滤时过多的放射性会损失</td><td> ·使用前请先过滤。 </td></tr><tr><td> ·使用死体积较小的过滤器。 </td></tr><tr><td rowspan="4"> HPLC上的最终产品峰值看起来很宽泛</td><td> ·注入量过多注入较低&#39;mount。使用较大直径的色谱柱。 </td></tr><tr><td> ·柱子调节不好为柱子设置至少30列色谱柱。 </td></tr><tr><td> ·流动相的pH值较低。确保pH≥8。 </td></tr><tr><td> ·栏状态不佳替换列。使用与碱性pH相容的色谱柱。 </td></tr></tbody></table> 表2.故障排除指南。

Watch this Scientific Journal Video about Automated Radiochemical Synthesis of [18F]3F4AP: A Novel PET Tracer for Imaging Demyelinating Diseases at JoVE.com

Automated Radiochemical Synthesis of [18F]3F4AP: A Novel PET Tracer for Imaging Demyelinating Diseases

我们展示了[ 18 F] 3F4AP和质量控制程序的半自动放射化学合成。

自动放射化学合成[<sup&gt; 18</sup&gt; F] 3F4AP:一种用于成像脱髓鞘疾病的新型PET示踪剂

3-[18F]fluoro-4-aminopyridine, [18F]3F4AP, is a radiofluorinated analog of the FDA-approved drug for multiple sclerosis 4-aminopyridine (4AP). This ...

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Automated Radiochemical Synthesis of [18F]3F4AP: A Novel PET Tracer for Imaging Demyelinating Diseases

9.9K 次观看.  The University of Chicago. 我们展示了[ 18 F] 3F4AP和质量控制程序的半自动放射化学合成。 

视频: Automated Radiochemical Synthesis of [18F]3F4AP: A Novel PET Tracer for Imaging Demyelinating Diseases

Radionuclide-fluorescence Reporter Gene Imaging to Track Tumor Progression in Rodent Tumor Models

Metastasis is responsible for most cancer deaths. Despite extensive research, the mechanistic understanding of the complex processes governing metastasis remains incomplete. In vivo models are paramount for metastasis research, but require refinement. Tracking spontaneous metastasis by non-invasive in vivo imaging is now possible, but remains challenging as it requires long-time observation and high sensitivity. We describe a longitudinal combined radionuclide and fluorescence whole-body in vivo imaging approach for tracking tumor progression and spontaneous metastasis. This reporter gene methodology employs the sodium iodide symporter (NIS) fused to a fluorescent protein (FP). Cancer cells are engineered to stably express NIS-FP followed by selection based on fluorescence-activated cell sorting. Corresponding tumor models are established in mice. NIS-FP expressing cancer cells are tracked non-invasively in vivo at the whole-body level by positron emission tomography (PET) using the NIS radiotracer [18F]BF4-. PET is currently the most sensitive in vivo imaging technology available at this scale and enables reliable and absolute quantification. Current methods either rely on large cohorts of animals that are euthanized for metastasis assessment at varying time points, or rely on barely quantifiable 2D imaging. The advantages of the described method are: (i) highly sensitive non-invasive in vivo 3D PET imaging and quantification, (ii) automated PET tracer production, (iii) a significant reduction in required animal numbers due to repeat imaging options, (iv) the acquisition of paired data from subsequent imaging sessions providing better statistical data, and (v) the intrinsic option for ex vivo confirmation of cancer cells in tissues by fluorescence microscopy or cytometry. In this protocol, we describe all steps required for routine NIS-FP-afforded non-invasive in vivo cancer cell tracking using PET/CT and ex vivo confirmation of in vivo results. This protocol has applications beyond cancer research whenever in vivo localization, expansion and long-time monitoring of a cell population is of interest.

We describe a protocol for preclinical in vivo tracking of cancer metastasis. It is based on a radionuclide-fluorescence reporter combining the sodium iodide symporter, detected by non-invasive [18F]tetrafluoroborate-PET, and a fluorescent protein for streamlined ex vivo confirmation. The method is applicable for preclinical in vivo cell tracking beyond tumor biology.

核素荧光报告基因成像在啮齿动物肿瘤模型中跟踪肿瘤进展

Metastasis is responsible for most cancer deaths. Despite extensive research, the mechanistic understanding of the complex processes governing metastasis ...

科研

癌症研究

Automation of a Positron-emission Tomography (PET) Radiotracer Synthesis Protocol for Clinical Production

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological targets and processes. However, the increasing number of different tracers creates challenges for their production at radiopharmacies. While historically it has been practical to dedicate a custom-configured radiosynthesizer and hot cell for the repeated production of each individual tracer, it is becoming necessary to change this workflow. Recent commercial radiosynthesizers based on disposable cassettes/kits for each tracer simplify the production of multiple tracers with one set of equipment by eliminating the need for custom tracer-specific modifications. Furthermore, some of these radiosynthesizers enable the operator to develop and optimize their own synthesis protocols in addition to purchasing commercially-available kits. In this protocol, we describe the general procedure for how the manual synthesis of a new PET tracer can be automated on one of these radiosynthesizers and validated for the production of clinical-grade tracers. As an example, we use the ELIXYS radiosynthesizer, a flexible cassette-based radiochemistry tool that can support both PET tracer development efforts, as well as routine clinical probe manufacturing on the same system, to produce [18F]Clofarabine ([18F]CFA), a PET tracer to measure in vivo deoxycytidine kinase (dCK) enzyme activity. Translating a manual synthesis involves breaking down the synthetic protocol into basic radiochemistry processes that are then translated into intuitive chemistry &#34;unit operations&#34; supported by the synthesizer software. These operations can then rapidly be converted into an automated synthesis program by assembling them using the drag-and-drop interface. After basic testing, the synthesis and purification procedure may require optimization to achieve the desired yield and purity. Once the desired performance is achieved, a validation of the synthesis is carried out to determine its suitability for the production of the radiotracer for clinical use.

Automation of a Positron-emission Tomography PET Radiotracer Synthesis Protocol for Clinical Production

Positron-emission tomography (PET) imaging sites that are involved in multiple early clinical research trials need robust and versatile radiotracer manufacturing capabilities. Using the radiotracer [18F]Clofarabine as an example, we illustrate how to automate the synthesis of a radiotracer using a flexible, cassette-based radiosynthesizer and validate the synthesis for clinical use.

用于临床生产的正电子发射层析成像 (PET) 放射性同位素示踪合成协议的自动化

The development of new positron-emission tomography (PET) tracers is enabling researchers and clinicians to image an increasingly wide array of biological ...

化学

Radiotracer Administration for High Temporal Resolution Positron Emission Tomography of the Human Brain: Application to FDG-fPET

Functional positron emission tomography (fPET) provides a method to track molecular targets in the human brain. With a radioactively-labelled glucose analogue, 18F-fluordeoxyglucose (FDG-fPET), it is now possible to measure the dynamics of glucose metabolism with temporal resolutions approaching those of functional magnetic resonance imaging (fMRI). This direct measure of glucose uptake has enormous potential for understanding normal and abnormal brain function and probing the effects of metabolic and neurodegenerative diseases. Further, new advances in hybrid MR-PET hardware make it possible to capture fluctuations in glucose and blood oxygenation simultaneously using fMRI and FDG-fPET.
The temporal resolution and signal-to-noise of the FDG-fPET images is critically dependent upon the administration of the radiotracer. This work presents two alternative continuous infusion protocols and compares them to a traditional bolus approach. It presents a method for acquiring blood samples, time-locking PET, MRI, experimental stimulus, and administering the non-traditional tracer delivery. Using a visual stimulus, the protocol results show cortical maps of the glucose-response to external stimuli on an individual level with a temporal resolution of 16 s.

This manuscript describes two radiotracer administration protocols for FDG-PET (constant infusion and bolus plus infusion) and compares them to bolus administration. Temporal resolutions of 16 s are achievable using these protocols.

人脑高时态分辨率正态发射断层扫描的放射跟踪器管理:在FDG-fPET中的应用

Functional positron emission tomography (fPET) provides a method to track molecular targets in the human brain. With a radioactively-labelled glucose ...

行为学

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands for in vivo investigations. Within this protocol, a robust and reliable remote-controlled radiosynthesis of [11C]SNAP-7941, an antagonist to the melanin-concentrating hormone receptor 1, is described. The radiosynthesis starts with cyclotron produced [11C]CO2 that is subsequently further reacted via a gas-phase transition to [11C]CH3OTf. Then, this reactive intermediate is introduced to the precursor solution and forms the respective radiotracer. Chemical as well as the radiochemical purity are determined by means of RP-HPLC, routinely implemented in the radiopharmaceutical quality control process. Additionally, the molar activity is calculated as it is a necessity for the following real-time kinetic investigations. Furthermore, [11C]SNAP-7941 is applied to MDCKII-WT and MDCKII-hMDR1 cells for evaluating the impact of P-glycoprotein (P-gp) expression on cell accumulation. For this reason, the P-gp expressing cell line (MDCKII-hMDR1) is either used without or with blocking prior to experiments by means of the P-gp substrate (&#177;)-verapamil and the results are compared to the ones observed for the wildtype cells. The overall experimental approach demonstrates the importance of a precise time-management that is essential for every preclinical and clinical study using PET tracers radiolabelled with short-lived nuclides, such as carbon-11 (half-life: 20 min).

Technical Aspect of the Automated Synthesis and Real-Time Kinetic Evaluation of [11C]SNAP-7941

Here, we represent a protocol for the fully automated radiolabelling of [11C]SNAP-7941 and the analysis of the real-time kinetics of this PET-tracer on P-gp expressing and non-expressing cells.

[11C_SNAP-7941] 自动合成和实时动力学评估的技术方面

Positron emission tomography (PET) is an essential molecular imaging technique providing insights into pathways and using specific targeted radioligands ...

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a non-radioactive precursor in solution. This approach necessitates purification of the tracer by high performance liquid chromatography (HPLC) followed by reformulation in a biocompatible solvent for human administration. We recently developed a novel 11C-methylation approach for the highly efficient synthesis of carbon-11 labeled PET radiopharmaceuticals, taking advantage of solid phase cartridges as disposable &#34;3-in-1&#34; units for the synthesis, purification and reformulation of the tracers. This approach obviates the use of preparative HPLC and reduces the losses of the tracer in transfer lines and due to radioactive decay. Furthermore, the cartridge-based technique improves synthesis reliability, simplifies the automation process and facilitates compliance with the Good Manufacturing Practice (GMP) requirements. Here, we demonstrate this technique on the example of production of a PET tracer Pittsburgh compound B ([11C]PiB), a gold standard in vivo imaging agent for amyloid plaques in the human brains.

Solid Phase 11C-Methylation, Purification and Formulation for the Production of PET Tracers

We report an efficient carbon-11 radiolabeling technique to produce clinically relevant tracers for Positron Emission Tomography (PET) using solid phase extraction cartridges. 11C-methylating agent is passed through a cartridge preloaded with precursor and successive elution with aqueous ethanol provides chemically and radiochemically pure PET tracers in high radiochemical yields.

用于生产PET示踪剂的固体阶段11C甲基化、纯化和配方

Routine production of radiotracers used in positron emission tomography (PET) mostly relies on wet chemistry where the radioactive synthon reacts with a ...

18F-Labeling of Radiotracers Functionalized with a Silicon Fluoride Acceptor (SiFA) for Positron Emission Tomography

The para-substituted di-tert-butylfluorosilylbenzene structural motif known as the silicon-fluoride acceptor (SiFA) is a useful tag in the radiochemist&#39;s toolkit for incorporating radioactive [18F]fluoride into tracers for use in positron emission tomography. In comparison to conventional radiolabeling strategies, isotopic exchange of fluorine-19 from SiFA with [18F]fluoride is carried out at room temperature and requires minimal reaction participants. The formation of by-products is thus negligible, and purification is greatly simplified. However, while the precursor molecule used for labeling and the final radiolabeled product are isotopically discrete, they are chemically identical and are thus inseparable during purification procedures. The SiFA tag is also susceptible to degradation under the basic conditions arising from the processing and drying of [18F]fluoride. The &#39;4 drop method&#39;, wherein only the first 4 drops of eluted [18F]fluoride are used from the solid-phase extraction, reduces the amount of base in the reaction, facilitates lower molar amounts of precursor, and reduces degradation.

18F-Labeling of Radiotracers Functionalized with a Silicon Fluoride Acceptor SiFA for Positron Emission Tomography

The synthesis of fluorine-18 (18F) labeled radiopharmaceuticals for positron emission tomography typically requires months of experience. When incorporated into a radiotracer, the silicon-fluoride acceptor (SiFA) motif enables a simple 18F-labeling protocol that is independent of costly equipment and preparatory training, while reducing precursor quantity needed and utilizing milder reaction conditions.

18放射性跟踪器的F-标签，其功能与硅氟化物接受器（SiFA）进行正电子发射断层扫描

The para-substituted di-tert-butylfluorosilylbenzene structural motif known as the silicon-fluoride acceptor (SiFA) is a useful tag in the ...

Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol

The kynurenine pathway (KP) is a primary route for tryptophan metabolism. Evidence strongly suggests that metabolites of the KP play a vital role in tumor proliferation, epilepsy, neurodegenerative diseases, and psychiatric illnesses due to their immune-modulatory, neuro-modulatory, and neurotoxic effects. The most extensively used positron emission tomography (PET) agent for mapping tryptophan metabolism, &#945;-[11C]methyl-L-tryptophan ([11C]AMT), has a short half-life of 20 min with laborious radiosynthesis procedures. An onsite cyclotron is required to radiosynthesize [11C]AMT. Only a limited number of centers produce [11C]AMT for preclinical studies and clinical investigations. Hence, the development of an alternative imaging agent that has a longer half-life, favorable in vivo kinetics, and is easy to automate is urgently needed. The utility and value of 1-(2-[18F]fluoroethyl)-L-tryptophan, a fluorine-18-labeled tryptophan analog, has been reported in preclinical applications in cell line-derived xenografts, patient-derived xenografts, and transgenic tumor models.
This paper presents a protocol for the radiosynthesis of 1-(2-[18F]fluoroethyl)-L-tryptophan using a one-pot, two-step strategy. Using this protocol, the radiotracer can be produced in a 20 &#177; 5% (decay corrected at the end of synthesis, n &#62; 20) radiochemical yield, with both radiochemical purity and enantiomeric excess of over 95%. The protocol features a small precursor amount with no more than 0.5 mL of reaction solvent in each step, low loading of potentially toxic 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (K222), and an environmentally benign and injectable mobile phase for purification. The protocol can be easily configured to produce 1-(2-[18F]fluoroethyl)-L-tryptophan for clinical investigation in a commercially available module.

Radiosynthesis of 1-2-[18F]Fluoroethyl-L-Tryptophan using a One-pot, Two-step Protocol

Here, we describe the radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-tryptophan, a positron emission tomography imaging agent for studying tryptophan metabolism, using a one-pot, two-step strategy in a radiochemistry synthesis system with good radiochemical yields, high enantiomeric excess, and high reliability.

1-（2-[18F]氟乙基）-L-色氨酸的放射性合成，采用一锅两步实验方案

The kynurenine pathway (KP) is a primary route for tryptophan metabolism. Evidence strongly suggests that metabolites of the KP play a vital role in tumor ...

Automated Production of [68Ga]Ga-FAPI-46 on the iPHASE MultiSyn Synthesizer

An Automated Radiosynthesis of [68Ga]Ga-FAPI-46 for Routine Clinical Use

[68Ga]Ga-FAPI-46 is a promising new tracer for the imaging of fibroblast activation protein (FAP) by positron emission tomography (PET). Labeled FAP inhibitors (FAPIs) have demonstrated uptake in various types of cancers, including breast, lung, prostate, pancreatic and colorectal cancer. FAPI-PET also possesses a practical advantage over FDG-PET as fasting and resting are not required. [68Ga]Ga-FAPI-46 exhibits enhanced pharmacokinetic properties, improved tumor retention, and higher contrast images than the earlier presented [68Ga]Ga-FAPI-02 and [68Ga]Ga-FAPI-04. Although a manual synthesis protocol for [68Ga]Ga-FAPI-46 was initially described, in recent years, automated methods using different commercial synthesizers have been reported.
In this work, we describe the development of the automated synthesis of [68Ga]Ga-FAPI-46 using the iPHASE MultiSyn synthesizer for clinical applications. Initially, optimization of the reaction time and comparison of the performance of four different solid phase extraction (SPE) cartridges for final product purification were investigated. Then, the development and validation of the production of 0.6-1.7 GBq of [68Ga]Ga-FAPI-46 were conducted using these optimized parameters. The product was synthesized in 89.8 &#177; 4.8% decay corrected yield (n = 6) over 25 min. The final product met all recommended quality control specifications and was stable up to 3 h post synthesis.

This work describes the automated production of up to 1.7 GBq of [68Ga]Ga-FAPI-46 on the iPHASE MultiSyn synthesizer for PET imaging of fibroblast activation protein.

[68Ga]Ga-FAPI-46 is a promising new tracer for the imaging of fibroblast activation protein (FAP) by positron emission tomography (PET). Labeled FAP ...

Microwave-assisted One-pot Synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB)

Biomolecules, including peptides,1-9 proteins,10,11 and antibodies and their engineered fragments,12-14 are gaining importance as both potential therapeutics and molecular imaging agents. Notably, when labeled with positron-emitting radioisotopes (e.g., Cu-64, Ga-68, or F-18), they can be used as probes for targeted imaging of many physiological and pathological processes.15-18 Therefore, significant effort has devoted to the synthesis and exploration of 18F-labeled biomolecules. Although there are elegant examples of the direct 18F-labeling of peptides,19-22 the harsh reaction conditions (i.e., organic solvent, extreme pH, high temperature) associated with direct radiofluorination are usually incompatible with fragile protein samples. To date, therefore, the incorporation of radiolabeled prosthetic groups into biomolecules remains the method of choice.23,24
N-Succinimidyl-4-[18F]fluorobenzoate ([18F]SFB),25-37 a Bolton-Hunter type reagent that reacts with the primary amino groups of biomolecules, is a very versatile prosthetic group for the 18F-labeling of a wide spectrum of biological entities, in terms of its evident in vivo stability and high radiolabeling yield. After labeling with [18F]SFB, the resulting [18F]fluorobenzoylated biomolecules could be explored as potential PET tracers for in vivo imaging studies.1 Most [18F]SFB radiosyntheses described in the current literatures require two or even three reactors and multiple purifications by using either solid phase extraction (SPE) or high-performance liquid chromatography (HPLC). Such lengthy processes hamper its routine production and widespread applications in the radiolabeling of biomolecules. Although several module-assisted [18F]SFB syntheses have been reported,29-32, 41-42 they are mainly based on complicated and lengthy procedures using costly commercially-available radiochemistry boxes (Table 1). Therefore, further simplification of the radiosynthesis of [18F]SFB using a low-cost setup would be very beneficial for its adaption to an automated process.
Herein, we report a concise preparation of [18F]SFB, based on a simplified one-pot microwave-assisted synthesis (Figure 1). Our approach does not require purification between steps or any aqueous reagents. In addition, microwave irradiation, which has been used in the syntheses of several PET tracers,38-41 can gives higher RCYs and better selectivity than the corresponding thermal reactions or they provide similar yields in shorter reaction times.38 Most importantly, when labeling biomolecules, the time saved could be diverted to subsequent bioconjugation or PET imaging step.28,43 The novelty of our improved [18F]SFB synthesis is two-fold: (1) the anhydrous deprotection strategy requires no purification of intermediate(s) between each step and (2) the microwave-assisted radiochemical transformations enable the rapid, reliable production of [18F]SFB.

Microwave-assisted One-pot Synthesis of N-succinimidyl-4-[18F]fluorobenzoate [18F]SFB

A facile, one-pot synthesis of N-succinimidyl-4-[18F]fluorobenzoate ([18F]SFB) was developed based on a non-aqueous, three-step radiochemical process. Using microwave heating, the entire procedure can be completed in less than 30 min, or 60 min with further purification by preparative HPLC. The decay-corrected radiochemical yields (RCYs) were 35-5% (n > 30).

微波辅助合成一锅 N -琥珀酰亚胺- 4 - [ 18 F] fluorobenzoate（[ 18 F] SFB）

Biomolecules, including peptides,1-9 proteins,10,11 and antibodies and their engineered fragments,12-14 are gaining importance as both potential ...

生物学

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

Patients with severe traumatic brain injury (sTBI) have difficulty knowing whether they are accurately expressing their thoughts and emotions because of disorders of consciousness, disrupted higher brain function, and verbal disturbances. As a consequence of an insufficient ability to communicate, objective evaluations are needed from family members, medical staff, and caregivers. One such evaluation is the assessment of functioning brain areas. Recently, multimodal brain imaging has been used to explore the function of damaged brain areas. [18F]-fluorodeoxyglucose positron emission tomography-computed tomography ([18F]FDG-PET/CT) is a successful tool for examining brain function. However, the assessment of brain glucose metabolism based on [18F]FDG-PET/CT is not standardized and depends on several varying parameters, as well as the patient&#39;s condition. Here, we describe a series of semiquantitative assessment protocols for a region-of-interest (ROI) image analysis using self-produced [18F]FDG tracers in patients with sTBI. The protocol focuses on screening the participants, preparing the [18F]FDG tracer in the hot lab, scheduling the acquisition of [18F]FDG-PET/CT brain images, and measuring glucose metabolism using the ROI analysis from a targeted brain area.

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

[18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is useful for studying glucose metabolism related to brain function. Here, we present a protocol for an [18F]FDG tracer set-up and semiquantitative assessment of the region-of-interest analysis for targeted brain areas associated with clinical manifestations in patients with severe traumatic brain injury.

[18f] fdg 示踪剂在重型颅脑损伤患者中的半定量评价

Patients with severe traumatic brain injury (sTBI) have difficulty knowing whether they are accurately expressing their thoughts and emotions because of ...

自动放射化学合成[

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1-（2-[^18F]氟乙基）-L-色氨酸的放射性合成，采用一锅两步实验方案

An Automated Radiosynthesis of [⁶⁸Ga]Ga-FAPI-46 for Routine Clinical Use

微波辅助合成一锅 N -琥珀酰亚胺- 4 - [¹⁸ F] fluorobenzoate（[¹⁸ F] SFB）

[¹⁸f] fdg 示踪剂在重型颅脑损伤患者中的半定量评价