Title:
音響共振器を有する磁気共鳴イメージング(MRI)システム
Document Type and Number:
Japanese Patent JP2005524509
Kind Code:
A
Abstract:
The invention relates to a magnetic resonance imaging (MRI) system ( 1 ) comprising an examination volume ( 11 ), a main magnet system ( 17 ) for generating a magnetic field (B 0 ) in the examination volume, and a gradient magnet system ( 25 ) for generating altering gradients of the magnetic field in the examination volume. The gradient magnet system is accommodated in a housing ( 31 ) having a main wall ( 33 ) facing the examination volume and a substantially conical wall ( 35 ) facing away from the examination volume. The main wall and the conical wall enclose a substantially angular tip portion ( 47 ) of the housing. In order to limit the level of the acoustic vibrations in and around the MRI system ( 1 ) caused by mechanical vibrations of the angular tip portion ( 47 ), the MRI system comprises a plurality of acoustic resonators ( 55 ) which each comprise an elongate resonance volume ( 57 ) with an open end ( 59 ) and a closed end ( 61 ) and a length (L) between the open end and the closed end. The open ends of the resonators are arranged near the angular tip portion, and the length of the resonators is substantially equal to 0.25 k*(, wherein k=1, 3, 5, 7, . . . , and wherein ( is the wavelength of an acoustic wave caused by mechanical vibrations of the angular tip portion. The resonators have the acoustic property of neutralizing acoustic waves having said wavelength (. Preferably, the length of the resonators is tuned to at least one of the wavelengths corresponding to the mechanical resonance frequencies of the vibrating angular tip portion, as the acoustic waves originating from the vibrations at these resonance frequencies constitute a main portion of the overall acoustic level of the MRI system.
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Inventors:
Rosen Nicolas Bee
Lagrange Martein Earl
Halvey Paul Earl
Rim Pence Patrick Dave Rupee
Ham Cornelis Elsey
Lagrange Martein Earl
Halvey Paul Earl
Rim Pence Patrick Dave Rupee
Ham Cornelis Elsey
Application Number:
JP2004503969A
Publication Date:
August 18, 2005
Filing Date:
April 11, 2003
Export Citation:
Assignee:
Koninklijke Philips Electronics N.V.
International Classes:
A61B5/055; G01R33/385; (IPC1-7): A61B5/055
Attorney, Agent or Firm:
Susumu Tsugaru
Akihiko Miyazaki
Fueda Shusen
Akihiko Miyazaki
Fueda Shusen