RF current density imaging with a clinical magnetic resonance image

Current density imaging (CDI) is a technique which uses a magnetic resonance imager to produce an image of the current density in a subject produced by an external source. The development of CDI began at the University of Toronto in 1987. Radio frequency-current density imaging (RF-CDI) is a form of CDI where the externally applied current is RF. The technique of RF-CDI has been demonstrated on a small bore experimental imager operating at 86.5 MHz. To image subjects larger than small animals it is necessary to develop the technique on a large bore clinical MR imager that can accommodate subjects as large as humans.;This thesis describes the research and development of an RF-CDI system that uses a 1.5 Tesla, General Electric Signa clinical MR imager. To produce images of the magnetic fields and current density of externally applied current very precise temporal, frequency and phase relationships between the external current and the RF field of the imager must be established. In this thesis the requirements associated with generating a current pulse that establishes these relationships are developed, as are the interface requirements associated with connecting external hardware to the imager. A detailed design that consists of both custom built hardware and software modules which satisfies the requirements is presented. The performance of the implemented system is measured and compared with the theoretical ideals.