An open-access magnetic resonance imaging (MRI) system is being developed for use in research on orientational/ gravitational effects on lung physiology and function. The open-access geometry enables study of human subjects in diverse orientations. This system operates at a magnetic flux density, considerably smaller than the flux densities of typical other MRI systems, that can be generated by resistive electromagnet coils (instead of the more-expensive superconducting coils of the other systems).

The human subject inhales air containing 3He or 129Xe atoms, the nuclear spins of which have been polarized by use of a laser beam to obtain a magnetic resonance that enables high-resolution gas space imaging at the low applied magnetic field. The system includes a bi-planar, constant-current, four-coil electromagnet assembly and associated electronic circuitry to apply a static magnetic field of 6.5 mT throughout the lung volume; planar coils and associated circuitry to apply a pulsed magnetic-field-gradient for each spatial dimension; a single, detachable radio-frequency coil and associated circuitry for inducing and detecting MRI signals; a table for supporting a horizontal subject; and electromagnetic shielding surrounding the electromagnet coils.

This work was done by Ross W. Mair, Matthew S. Rosen, Leo L. Tsai, and Ronald L. Walsworth of the Harvard-Smithsonian Center for Astrophysics; Mirko I. Hrovat of Mirtech, Inc.; Samuel Patz of Brigham and Women’s Hospital; and Iullian C. Ruset and F. William Hersman of the University of New Hampshire for Johnson Space Center.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

Harvard-Smithsonian Center for Astrophysics
Cambridge, MA 02138

Refer to MSC-24182-1/3-1, volume and number of this NASA Tech Briefs issue, and the page number.

Medical Design Briefs Magazine

This article first appeared in the May, 2009 issue of Medical Design Briefs Magazine.

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