RECYCLE OF 3HE FOR HIGH-RESOLUTION LUNG IMAGING

稀有气体同位素由于其对核磁共振的高检测灵敏度，是非常有吸引力的成像剂。特别地，自旋极化的3He使得能够对肺和气道进行快速的气体空间成像，以用于临床诊断和生理研究。 不幸的是，3He的有限可用性严重限制了可以进行的高分辨率肺部成像研究的数量。 我们建议开发一种系统来回收和再循环稀有的氦同位素，这样高分辨率的肺部成像就可以变得普遍和便宜。 这项创新是一种低温气体分离系统，它可以从患者的呼出气流中提取和净化3He，并将其保存起来用于重新极化3和重新用于其他患者。 在第一阶段，我们将通过（1）执行概念验证测试来证明He回收系统的可行性，该测试证明了从呼出气体中有效分离、纯化和灭菌3He的可行性，以及（2）产生完整系统的概念设计来回收和再循环3He。 在第二阶段，我们将建立和展示一个完整的回收和再循环系统。拟议的商业应用：稀有稀有气体同位素如果能够经济地使用，将是医学成像的潜在突破。这些同位素的用途包括肺和气道的高分辨率气体空间成像、实用低场MRI、使用可溶性同位素的血液灌注和脑生理学研究以及基于气态同位素扩散的多孔介质研究。该计划开发的技术将使这些稀有同位素能够多次重复使用，从而使这些进步变得实用和经济。

Noble gas isotopes that can be nuclear spin-polarized are very attractive imaging agents ,because of their high detection sensitivity for nuclear magnetic resonance. In particular, spin-polarized 3He enables fast, gas- space imaging of the lungs and airways for clinical diagnosis and physiological studies. Unfortunately, the limited availability of 3He severely limits the number of high-resolution lung imaging studies that can be performed. We propose to develop a system to recover and recycle the rare helium isotope so that high-resolution lung imaging can become common and inexpensive. The innovation is a cryogenic gas separation system that extracts and purifies the 3He from a patient's exhalation stream and saves it for re-polarization3 and reuse in other patients. In Phase I we will prove the feasibility of the He recovery system by (l) performing a proof-of-concept test that demonstrates the feasibility of efficiently separating, purifying, and sterilizing the 3He from exhalation gases, and (2) producing a conceptual design of a complete system to recover and recycle 3He. In Phase II we will build and demonstrate a complete recovery and recycling system. PROPOSED COMMERCIAL APPLICATIONS: Rare, noble gas isotopes are a potential breakthrough for medical imaging if they could be used economically. Uses for these isotopes include high- resolution, gas-space imaging of the lungs and airways, practical low-field MRI, studies of blood perfusion and brain physiology using soluble isotopes, and porous media studies based on diffusion of gaseous isotopes. Technology developed in this program will make these advances practical and economical by enabling these rare isotopes to be reused many times.