SBIR Phase II: Boron Nitride Nanotube Cyclotron Targets for Recoil-Escape Production of Carbon-11 For PET/CT Medical Imaging

这一小型企业创新研究(SBIR)第二阶段项目旨在满足低成本按需剂量生产用于核医学中生物标记物和放射性示踪剂应用的碳-11同位素的需要。生物标志物和放射性示踪剂通常用于正电子发射断层扫描和计算机断层扫描(PET/CT)代谢成像，以支持研究、药物发现以及癌症和其他疾病的检测。它们还用于癌症的治疗分期，以确定治疗是否有效。常见的例子包括心脏的心肌灌注成像以可视化血流和功能，PET脑扫描以检测早期阿尔茨海默氏症和脑瘤，以及胆碱PET/CT用于前列腺癌的诊断和分期。碳-11是一种重要的放射性示踪剂/放射性药物，由于其能够很容易地被结合到许多分子中而不影响生物活性，因此具有独特的优势。碳-11目前是通过在高能商业回旋加速器上使用专门的靶材生产的。这些回旋加速器的安装成本高达数百万美元，而现有的靶子效率很低。低能回旋加速器的价格要低得多，目前正在由多家商业公司开发。该项目寻求开发一种新的回旋加速器靶标方法，使用独特的纳米材料以低能量生产碳-11，从而显著降低成本。该项目的智力优势在于，通过开发反冲逃逸靶标，使用新型纳米材料更高效、更低成本地生产碳-11。寻找一种既适合通过几种可用核反应中的一种有效生产碳-11，又适合以可用形式高效回收所产生的放射性示踪剂的良好靶材是具有挑战性的。产生的碳-11很难回收，因为它很容易被许多传统的目标材料捕获，导致产量低。纳米科学和技术的最新进展使生产具有独特特性的新材料成为可能。氮化硼纳米管(BNNT)由单原子厚度或最多几个原子厚度的纤维组成，允许使用低能量回旋加速器以二氧化碳气体的形式高效地生产和回收碳-11。原型生产目标将在商业回旋加速器基地开发和测试。收集产生的碳-11气体的过程将得到优化，以实现可用放射性示踪剂材料的最高产量。将努力进一步开发具有理想特性的BNNT材料，包括高纯度和最佳密度。

This Small Business Innovation Research (SBIR) Phase II project intends to meet the need for low cost dose-on-demand production of Carbon-11 isotope for biomarker and radiotracer applications in nuclear medicine. Biomarkers and radiotracers are commonly used for Positron Emission Tomography and Computed Tomography (PET/CT) metabolic imaging, in support of research, drug discovery, and detection of cancer and other illnesses. They are also used for therapy staging of cancer, to determine if treatment is effective. Common examples include myocardial perfusion imaging of the heart to visualize blood flow and function, PET scanning of the brain to detect early onset Alzheimer's and brain tumors, and Choline PET/CT for the diagnosis and staging of prostate cancer. Carbon-11 is an important radiotracer/radiopharmaceutical that offers unique advantages due to its ability to be easily incorporated into many molecules without impacting biological activity. Carbon-11 is currently produced by using specialized targets on high-energy commercial cyclotrons. These cyclotrons cost millions of dollars to install, and existing targets are inefficient. Low energy cyclotrons are significantly less expensive, and are currently under development by multiple commercial companies. This project seeks to develop a novel cyclotron target methodology for producing Carbon-11 at low energies using unique nanomaterials, resulting in significantly lower costs. The intellectual merit of this project is in the use of novel nanomaterials to produce Carbon-11 more efficiently and at lower cost, through development of recoil escape targets. It is challenging to find a good target material suitable for both efficient production of Carbon-11, by one of several available nuclear reactions, and efficient recovery of the produced radiotracer in a usable form. The produced Carbon-11 can be difficult to recover, as it is easily trapped in many conventional target materials, resulting in low yields. Recent advances in nanoscience and technology allow for production of novel materials with unique characteristics. Boron nitride nanotubes (BNNT) are composed of fibers with single atomic thickness, or at most a few atoms thick, allowing Carbon-11 to be efficiently produced and recovered in the form of carbon dioxide gas using low energy cyclotrons. Prototype production targets will be developed and tested at commercial cyclotron sites. The process for collecting the produced Carbon-11 gas will be optimized to achieve the highest yields of usable radiotracer material. Efforts will be made to further develop BNNT materials with ideal characteristics, including high purity and optimal density.