%0 Journal Article %T 3He Lung Imaging in an Open Access, Very-Low-Field Human MRI System %A R. W. Mair %A M. I. Hrovat %A S. Patz %A M. S. Rosen %A I. C. Ruset %A G. P. Topulos %A L. L. Tsai %A J. P. Butler %A F. W. Hersman %A R. L. Walsworth %J Physics %D 2004 %I arXiv %X The human lung and its functions are extremely sensitive to gravity, however the conventional high-field magnets used for most laser-polarized 3He MRI of the human lung restrict subjects to lying horizontally. Imaging of human lungs using inhaled laser-polarized 3He gas is demonstrated in an open-access very-low-magnetic-field (< 5 mT) MRI instrument. This prototype device employs a simple, low-cost electromagnet, with an open geometry that allows variation of the orientation of the imaging subject in a two-dimensional plane. As a demonstration, two-dimensional lung images were acquired with 4 mm in-plane resolution from a subject in two orientations: lying supine, and sitting in a vertical position with one arm raised. Experience with this prototype device will guide optimization of a second-generation very-low-field imager to enable studies of human pulmonary physiology as a function of subject orientation. %U http://arxiv.org/abs/physics/0403090v2