The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 12, 1992
Filed:
Dec. 08, 1989
Goh Miyajima, Katsuta, JP;
Takao Takahashi, Hitachi, JP;
Tuyosi Shudo, Katsuta, JP;
Shohei Suzuki, Takahagi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A magnetic field gradient coil system for use in a magnetic resonance imaging apparatus forming a magnetic field gradient in a direction of a Z-axis of an X, Y, Z orthogonal coordinate system having its origin at a selected position in the imaging apparatus comprises one pair of first coils and one pair of second coils having their centers on the Z-axis and having the same radius, the coils of each coil pair disposed symmetrically with respect to an XY plane including the origin, the coils of the second coil pair disposed more distant from the origin than the coils of the first coil pair, the coils of the first and second coil pairs disposed on one side of the origin supplied with current in the same direction, the coils disposed on the other side of the origin supplied with current opposite to the direction of current in the coils on the one side of the origin, each of the coils of the first coil pair disposed where the value of the Z-axis magnetic field component of first order at a selected position on the Z-axis becomes substantially maximum, and the ampere-turn and position of each of the coils of the second coil pair selected so that, at the selected position, the Z-axis magnetic field components of third and fifth orders provided by the second coil pair have values which can substantially cancel the Z-axis magnetic field components of third and fifth orders provided by the first coil pair.