Gilbert K M, Handler W B, Scholl T J, Odegaard J W, Chronik B A
Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, N6A 3K7, Canada.
Phys Med Biol. 2006 Jun 7;51(11):2825-41. doi: 10.1088/0031-9155/51/11/010. Epub 2006 May 17.
This paper presents a design study for a field-cycled magnetic resonance imaging (MRI) system directed at small animal imaging applications. A field-cycled MRI system is different from a conventional MRI system in that it uses two separate and dynamically controllable magnetic fields. A strong magnetic field is used to polarize the object, and a relatively weak magnetic field is used during signal acquisition. The potential benefits of field-cycled MRI are described. The theoretical dependences of field-cycled MRI performance on system design are introduced and investigated. Electromagnetic, mechanical and thermal performances of the system were considered in this design study. A system design for imaging 10 cm diameter objects is presented as an example, capable of producing high-duty-cycle polarizing magnetic fields of 0.5 T and readout magnetic fields corresponding to a proton Larmor frequency of 5 MHz. The specifications of the final design are presented along with its expected electromagnetic and thermal performance.
本文介绍了一种针对小动物成像应用的场循环磁共振成像（MRI）系统的设计研究。场循环MRI系统与传统MRI系统的不同之处在于，它使用两个独立且可动态控制的磁场。强磁场用于使物体极化，而在信号采集期间使用相对较弱的磁场。文中描述了场循环MRI的潜在优势。介绍并研究了场循环MRI性能对系统设计的理论依赖性。在本设计研究中考虑了系统的电磁、机械和热性能。给出了一个用于对直径10厘米物体进行成像的系统设计示例，该系统能够产生0.5 T的高占空比极化磁场以及对应于质子拉莫尔频率5 MHz的读出磁场。给出了最终设计的规格及其预期的电磁和热性能。
