公开(公告)号：US20050219026A1

公开(公告)日：2005-10-06

申请号：US10513625

申请日：2003-04-11

申请人： Nicholaas Roozen ,  Martijn La Grange ,  Paul Harvey ,  Patrick Limpens ,  Cornelis Ham ,  Nicolaas Roozen ,  Martijn La Grange

发明人： Nicholaas Roozen ,  Martijn La Grange ,  Paul Harvey ,  Patrick Limpens ,  Cornelis Ham ,  Nicolaas Roozen ,  Martijn La Grange

IPC分类号： A61B5/055 ,  G01R33/385 ,  H01F1/00

CPC分类号： G01R33/3854

摘要： 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 (B0) 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.

摘要翻译： 本发明涉及一种磁共振成像（MRI）系统（1），包括检查体积（11），用于在检查体积中产生磁场（B 0）的主磁体系统（17）和梯度磁体系统 25）用于在检查体积中产生磁场的改变梯度。 倾斜磁体系统容纳在具有面向检查体积的主壁（33）的壳体（31）中，以及背离检查体积的基本上圆锥形的壁（35）。 主壁和锥形壁围绕壳体的基本角度的尖端部分（47）。 为了限制由角尖端部分（47）的机械振动引起的MRI系统（1）内和周围的声振动的水平，MRI系统包括多个声谐振器（55），每个声谐振器包括细长共振 在开口端和封闭端之间具有开口端（59）和封闭端（61）和长度（L）的容积（57）。 谐振器的开放端设置在角尖端附近，谐振器的长度基本上等于0.25k *（其中k = 1,3,5,7等等，其中（是波长 谐振器具有具有所述波长的中和声波的声学特性（优选地，谐振器的长度被调谐到与机械谐振相对应的至少一个波长 作为源自这些共振频率的振动的声波，振动角尖端部分的频率构成MRI系统的整体声级的主要部分。