Polarized Xenon Production: Multi-liter Accumulation

偏振氙气生产：多升积累

• 批准号: 7105083
• 负责人: Jan H Distelbrink
• 金额: $ 37.86万
• 依托单位: XEMED, LLC
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-03 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7105083
• 关键词: bioimaging /biomedical imaging; biomedical equipment development; clinical research; computer program /software; computer system hardware; contrast media; freezing; lung imaging /visualization /scanning; magnetic resonance imaging; optical polarization; xenon

Hyperpolarized gases, both xenon-129 and helium-3, have demonstrated utility in structural and functional lung imaging and quantifying lung disease. In contrast to helium-3, however, xenon is cheap and abundant. Its lower diffusion constant offers scientific advantages over helium, offsetting the disadvantage of its lower gyromagnetic ratio. Availability of a polarizer producing six liters per hour (a liter every ten minutes) at 50% polarization, almost a factor of one-hundred over most existing polarizers, would trigger widespread investigations and applications of hyperpolarized xenon as an imaging agent. The UNH group demonstrated a new type of xenon polarizer that flows the gas mixture at relatively high velocity and low pressure along a direction opposite to the laser beam. This polarizer demonstrated polarization of over 60% for small quantities and 20% for a production rate of over four liters per hour. The figure-of-merit (polarization times production rate) of this polarizer presently exceeds all other polarizer technologies by an order of magnitude. We propose to increase the output by another factor of six to ten. The cryogenic technology routinely used to accumulate hyperpolarized xenon recovers only 60% to 80% of the produced polarization for a fraction of a liter and far less for larger accumulations. Our new technique proposed for Phase I STTR successfully demonstrated 100% recovery for one-half liter and 88% recovery for one liter. We fabricated a prototype freeze-out cell, implemented an automated moving cryostat, and tested the device on our existing polarizer. Furthermore, we solved the critical materials question to produce a scalable implementation. Simple extensions of this implementation offer accumulation and full recovery of virtually unlimited quantities of hyperpolarized xenon. In Phase II we propose to increase the capacity of the accumulator, improve the control hardware and software, and simplify and automate the thawing procedure. We also comprehensively address the remaining limitations to scaling up the entire polarizer: polarizer column glassware design, gas flow parameters, and vacuum capacity. Increasing laser output and reducing the physical size of the polarizer are separately funded STTRs. These combined developments will scale up our laboratory prototype and convert it to a practical commercially-available hospital-based device.

超极化气体，氙气-129和氦-3，已经显示出在结构和 肺功能成像和肺部疾病的量化。然而，与氦-3不同的是，氙气既便宜又丰富。其较低的扩散常数提供了比氦更科学的优势，抵消了其较低旋磁比的缺点。在50%的偏振度下，每小时产生6升(每10分钟1升)的偏振器的可用性，几乎是大多数现有偏振器的100倍，将引发超极化氙气作为成像剂的广泛研究和应用。UNH小组展示了一种新型的氙气偏振器，它能以相对较高的速度和较低的压力使气体混合物沿着与激光束相反的方向流动。这种偏振器在小批量生产时偏振度超过60%，当生产速度超过每小时4升时偏振度为20%。这种偏振器的品质因数(偏振乘以产出率)目前超过了所有其他偏振器 技术进步了一个数量级。我们建议把产量再提高六到十倍。通常用来积累超极化氙气的低温技术，在一升以下的情况下只能恢复产生的极化的60%到80%，而对于更大的积累，则要少得多。我们为第一阶段STTR提出的新技术成功地证明了半升和一升的回收率分别为100%和88%。我们制作了一个原型冷冻室，实现了一个自动移动的低温恒温器，并在我们现有的偏振器上测试了该设备。此外，我们还解决了生产中的关键材料问题 可伸缩的实现。这种实现的简单扩展提供了几乎无限数量的超极化氙气的累积和完全恢复。在第二阶段，我们建议增加蓄能器的容量，改进控制硬件和软件，并简化和自动化解冻程序。我们还全面解决了扩大整个偏光镜的剩余限制：偏振镜柱玻璃器皿设计、气体流动参数和真空能力。增加激光输出和减小偏振器的物理尺寸是单独资助的STR。这些联合开发将扩大我们的实验室原型，并将其转化为实用的、可商业使用的医院设备。