Magnetic Resonance Imaging with Laser-Polarized He-3 and Xe-129 of Biological and Non-Biological Systems Using High Power Diode Lasers

9612244 Happer PI描述了一项跨学科计划，以研究一项革命性的新技术，该技术使用激光偏振气体来极大地增强生物腔(如肺和鼻窦)以及非生物系统的磁共振图像，这些系统包括陶瓷中的空洞等。最近，普林斯顿大学和杜克大学的研究人员合作，使用这项技术获得了人类肺部气体空间的第一张磁共振图像。该方法利用了普林斯顿大学开发的碱金属原子和惰性气体原子核之间的自旋交换相互作用的理解，从而使光学自旋极化成为可能。为了使它成为一种实用、低成本和广泛应用的生物和非生物系统成像技术，需要在我们对光学自旋极化物理的理解以及完成这一任务所必需的高功率激光二极管方面有重大的改进。在这个项目中，普林斯顿大学和威斯康星大学的研究人员将集中展示非常高功率、低成本、长寿命的无铝半导体激光阵列，其线宽足够窄，可以有效地偏振He-3和Xe-129，用于广泛的MRI应用。激光开发包括制造具有改进的载流子限制的新型MQW结构，以及实现窄线宽的分布式布拉格反射器和外腔结构，这将建立在普林斯顿大学和UW-Madison大学在高功率激光二极管方面的现有优势的基础上。为了改进MRI技术，PI将探索对溶解在血液和其他液体中的激光偏振气体进行成像的可能性。将研究提高自旋交换过程的效率和积累大量自旋极化气体的方法。***

9612244 Happer The PIs describe an interdisciplinary program to investigate a revolutionary new technology employing laser-polarized gases for greatly enhancing the magnetic resonance images (MRI) of biological cavities such as lungs and sinuses, as well as nonbiological systems which as voids in ceramics, etc. This technique was recently used to obtain the first MRI images of the gas space of a human lung by a collaboration between researchers at Princeton and Duke Universities. The method uses advances in optical spin polarization made possible through the understanding of spin exchange interactions between alkalimetal atoms and noble gas nuclei developed at Princeton. To make this a practical, low cost and widely applied technique for imaging both biological and non-biological systems, significant improvements in our understanding of the physics of optical spin polarization, as well as in the high power laser diodes necessary to accomplish this task are needed. In this project, researchers at Princeton and the University of Wisconsin will concentrate on the demonstration of very high power, low cost, long-lifetime Al-free diode laser arrays with linewidths sufficiently narrow to efficiently polarize He-3 and Xe-129 for a wide range of MRI applications. The laser development includes fabrication of novel MQW structures with improved carrier confinement, as well as distributed Bragg reflector and external cavity structures to achieve narrow linewidths, will build on existing strengths at both Princeton and UW-Madison in high power laser diodes. To improve the MRI technique, the PIs will explore the possibility of imaging laser polarized gases dissolved in blood and other liquids. Methods for increasing the efficiency of the spinexchange process, and for accumulating large quantities of spinpolarized gases will be investigated. ***