Polarized Xenon Production: Compact Magnetic Field

描述(申请人提供)：超极化气体，氙气-129和氦-3，已经证明了它们在结构和功能肺成像和量化肺部疾病方面的用途。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。如果一种紧凑、坚固的商用偏振器能够产生50%的偏振用于人体成像，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(偏振乘以生产率)目前比所有其他偏振器技术都高出一个数量级。单独的STTR项目以增加可用激光功率和低温积累能力将使偏振器的输出再增加6到10倍。偏振技术依赖于浸入均匀的25高斯场中的长偏振柱，具有100ppm均匀性的具有可调场的核磁共振区域，以及非常强的场积累区域。必须消除这些元素的相互作用，以使系统紧凑。我们的第一阶段STTR项目包括对新型非对称磁导率结构的数值模拟，以传输、塑造和传播磁力线，从而创建统一的场量和区域之间的平稳过渡。它还包括原型的制造和确认模拟和实现之间的一致性的测量。我们完成了数百个设计计算，制造并表征了2个样机，达到了设计标准。在第二阶段，我们建议进一步改进设计以提高性能，将偏振器组件集成到其新的磁环境中，并设计以便于接触内部组件，特别是最终的超极化氙气产品。这些发展将把我们的大型实验室原型转变为实用、紧凑、商业化的医院设备。

DESCRIPTION (provided by applicant): Hyperpolarized gases, both xenon-129 and helium-3, have demonstrated their 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 compact, robust, commercial polarizer producing 50% polarization in useful quantities for human imaging 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 4 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. Separate STTR projects to increase the useable laser power and to the cryogenic accumulation capacity would increase the polarizer output by another factor of 6 to 10. The polarization technology relies on a long polarization column immersed in a uniform 25 gauss field, an NMR region with adjustable field having 100 ppm uniformity, and a very strong field accumulation region. The interaction of these elements must be eliminated to make the system compact. Our Phase 1 STTR project included numerical simulation of novel asymmetric permeability structures to transport, shape, and spread magnetic field lines creating uniform field volumes and smooth transitions between regions. It also included fabrication of prototypes and measurements confirming the agreement between simulation and realization. We completed several hundred design calculations and fabricated and characterized 2 prototypes, meeting the design critera. In Phase II we propose to further refine the design for improved performance, intergrate the polarizer components into their new magnetic environment, and engineer for ease of access to internal components particularly the final hyperpolarized xenon product. These developments will convert our large laboratory prototype into a practical compact commercially-available hospital-based device.