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:
Dec. 04, 2001
Filed:
Oct. 28, 1999
Gerardus B. J. Mulder, Eindhoven, NL;
Cornelis L. G. Ham, Eindhoven, NL;
Aart J. Mateboer, Eindhoven, NL;
Nicolaas B. Roozen, Eindhoven, NL;
Johannes P. M. Verbunt, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
The MRI apparatus includes an actively shielded gradient system (,) with primary gradient coils and shielding coils (,). Despite the active shielding, such a system inevitably causes a magnetic field to some extent outside the shielding, so that eddy currents are generated in the conductive structures of the main magnet, said eddy currents causing heat dissipation and annoying noise. According to the invention, the gradient system also includes an eddy current shield (,) which consists of an electrically conductive, substantially closed plate; furthermore, the primary gradient coil (,) and the shielding coil (,) are arranged within the eddy current shield (,) and these three elements together constitute a mechanically rigid unit. As a result, eddy currents are avoided in the main magnet and annoying noise is strongly reduced.