T S Ibrahim et al 2001 Phys. Med. Biol. 46 609 doi:10.1088/0031-9155/46/2/324
T S Ibrahim1,2, R Lee1, B A Baertlein1 and P-M L Robitaille2,3
Show affiliationsThe finite-difference time-domain (FDTD) method is used to model a birdcage resonator. All the coil components, including the wires, lumped capacitors and the source, are geometrically modelled together. As such, the coupling effects within the birdcage, including the interactions of coil, source and human head, are accurately computed. A study of the transverse magnetic (B1) field homogeneity and the specific absorption rate (SAR) is presented on an anatomically detailed human head model at 64 and 200 MHz representing 1.5 and 4.7 T MRI systems respectively. Unlike that at 64 MHz, the B1 field distribution is found to be inhomogeneous at 200 MHz. Also, high local SAR values are observed in the tissue near the source due to the coupling between the source and the head at 200 MHz.
87.61.Tg Clinical applications
Issue 2 (February 2001)
Received 26 May 2000, in final form 30 October 2000
T S Ibrahim et al 2001 Phys. Med. Biol. 46 609
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