专利快速检索-快速检索全球专利，免费商用专利数据库-IPRDB

2. 发明公开

EP1199577A2 Magnetic resonance imaging using a tuning circuit for the transmit coil 审中-公开
标题翻译：成像通过使用调谐电路，用于在线圈的磁共振
公开(公告)号：EP1199577A2
公开(公告)日：2002-04-24
申请号：EP01308866.1
申请日：2001-10-18
申请人： Marconi Medical Sytems Finland Inc.
发明人： Lappalainen, Aatu Veikko Kalevi
IPC分类号： G01R33/36
CPC分类号： G01R33/3657 , G01R33/3628
摘要： A main magnetic field ( B 0 ) is applied through an imaging region. High power RF excitation or manipulation electrical pulses are applied to transmit coils. The transmit coil is inherently tuned to a frequency that is different from the resonance frequency of dipoles in the imaging region that are to be resonated. The transmit coil includes a reactive element (C t ) which is switched in and out of electrical communication with other inductive and capacitive portions (L), (C 0 ) of the transmit coil to change its tuning between the resonance and off-resonance frequencies. A rectifying diode (V 2 ) and a resistor are connected in parallel with the PIN diode (V 1 ) to rectify RF signals and generate a D.C. voltage across the resistor which biases the PIN diode to its conductive state. Preferably, before an RF excitation or manipulation electrical pulse is sent to the transmit coils, a tuning synthesizer (60) generates an off-resonance radio frequency pulse which is applied to the transmit coil, causing the rectifying diode and resistor to bias the PIN diode conductive, hence retune the transmit coil to the resonance frequency by the time the resonance frequency excitation or manipulation electrical signal is applied. After the radio frequency excitation or manipulation pulse is terminated, the PIN diode (V 1 ) switches non-conductive detuning through transmit coil. When the transmit coil is detuned, it does not interfere with a receive only coil (50) as it receives resonance signals from the resonating dipoles in the imaging region.
摘要翻译：主磁场（B 0）通过适用于成像区域。高功率射频激励或操纵的电脉冲被施加到发射线圈。发射线圈被固有调谐到的频率确实是从偶极子中那样将被共振成像区域的共振频率不同。发射线圈包括被进出交换电通信的与所述发射线圈的其它电感性和电容部（L），（C 0），以改变共振频率之间和偏共振其调谐电抗元件（CT）所有。的整流二极管，（V2）和电阻并联连接PIN二极管（V1），以纠正所述RF信号，并产生一个直流跨越其偏置，PIN二极管，以它的导通状态电阻的电压。优选地，前RF激励或操纵的电脉冲的合成器被发送到发射线圈，调谐（60）基因在偏共振的射频脉冲速率的所有被施加到发射线圈，使所述整流二极管和电阻，以偏置的PIN二极管导电的，因此，通过谐振频率激励或操纵的电信号的施加时间重新调谐发射线圈的谐振频率。射频激励脉冲或操纵结束后，PIN二极管（V1）通过切换发射线圈其他非导电性失谐。当发射线圈失谐，它不与一个只接收线圈（50），因为它接收来自于所述成像区中的共振的偶极子的共振信号干扰。

IPRDB

热门服务

关于我们

友情链接

联系方式