Demonstration of a compact compressor for application of metastability-exchange optical pumping of He-3 to human lung imaging

Hyperpolarized gas magnetic resonance imaging has recently emerged as a met hod to image lungs, sinuses, and the brain, The best lung images to date ha ve been produced using hyperpolarized He-3, which is produced by either spi n-exchange or metastability-exchange optical pumping. For hyperpolarized ga s MRI, the metastable method has demonstrated higher polarization levels an d higher polarizing rates, but it requires compression of the hyperpolarize d gas, Prior to this work, compression of hyperpolarized gas had only been accomplished using a large, complex and expensive apparatus. Here, human lu ng ventilation images are presented that were obtained using a compact comp ressor that is relatively simple and inexpensive, For this test, 1.1 bar-L of 15% hyperpolarized He-3 gas was produced at the National Institute of St andards and Technology using a modified commercial diaphragm pump. The hype rpolarized gas was transported to the University of Pennsylvania in a holdi ng field provided by a portable solenoid, (C) 2000 Wiley-Liss, Inc.