公开(公告)号：US07501828B1

公开(公告)日：2009-03-10

申请号：US12004150

申请日：2007-12-19

申请人： Wai Ha Wong ,  Alan R. Rath ,  Steven A. Suddarth

发明人： Wai Ha Wong ,  Alan R. Rath ,  Steven A. Suddarth

IPC分类号： G01V3/00

CPC分类号： G01R33/34046 ,  G01R33/34076 ,  G01R33/3657

摘要： A switchable birdcage coil functioning as a transmitter coil and a separate RF surface coil functioning as the receiver coil are utilize in NMR and MRI apparatus. To prevent the switchable birdcage coil from absorbing energy by coupling to the receiver coil or by absorbing power from the RF field produced by the precessing nuclear spins, one or more of the reactive elements of the birdcage coil are switched from a normal reactive impedance state to a high impedance state. The high impedance state is formed by switchably combining the reactive element with a complementary reactive element thereby forming parallel resonant high impedance circuit that is tuned to resonate at the NMR frequency.

摘要翻译： 用作发射器线圈的可切换鸟笼线圈和用作接收器线圈的单独的RF表面线圈在NMR和MRI装置中使用。 为了防止可切换的鸟笼线圈通过耦合到接收器线圈而吸收能量，或者通过从由进动的核自旋产生的RF场吸收功率，鸟笼线圈的一个或多个无功元件从正常的无功阻抗状态切换到 高阻抗状态。 高阻抗状态通过可变地组合无功元件与互补电抗元件形成，从而形成并联谐振高阻抗电路，其被调谐以在NMR频率下谐振。