Electromagnetic Design of High Frequency Probes for Magnetic Resonance
Speaker: Bin Betty Xu, ITEE
When: 2003-06-04 12:00:00
Venue: 78-420
Host: Prof. Stuart Croizer
Abstract:As MRI moves to higher field strengths in search of improved
resolution and signal-to-noise ratios, the size of RF coils relative
to the wavelength of operation becomes larger. Current and past
design procedures for RF coils, which have been quasi-static at
lower frequencies, become inaccurate and full wave methods and the
effect of the load must be used.
The high magnetic fields (frequency) technology has brought
considerable challenges in engineering in the form of ancillary
hardware, e.g., the radio frequency (RF) resonator. And a number of
so-called "high-field" MR systems operating at 3-4 T have been
developed. In order to make the electromagnetic design of high
frequency probes for magnetic resonance, analytical and numerical
analysis of several RF coils has been made. Equivalent LC circuit
method, MOM and FDTD have been used in the RF coils such as birdcage
coils, TEM coils, Cavity coils, Recav coils, millipede coil, Spiral
coil and some other designs of the RF coils. The B1 fields with and
without the load in the different frequencies have been
analysed. Equivalent LC circuit method has good approximation for
the simple geometry coils in low frequencies and in the high
magnetic fields (frequency) technology, the numerical studies are
performed based on a FDTD/MoM hybrid approach. The electromagnetic
interactions between the resonator/load and field/load are all
considered in the calculations. MoM is employed to evaluate the
currents distribution of the coil and several other currents
distribution analyses for the inverse method are produced. One
element of the project aims to produce an automated, inverse design
method for high frequency RF coils. Another aspect of the project is
to implement and compare FDTD analyses and design methods with an
optimal least squares Finite Element method.
Future work for the PhD project will be concentrated on the current
distribution analysis and inverse design method for high frequency
RF coils, MOM/FDTD will be used to aid the design process.
Biography:Bin Betty Xu was born in 1974 and got her bachelor's and master's
degrees of Electrical Engineering in Shandong University of
China. She enrolled in The university of Queensland to pursue her
PhD degree in April, 2002.
Her PhD project is Electromagnetic Design of High Frequency Probes
for Magnetic Resonance and her supervisor is Prof. Stuart Croizer.
Type: Ph.D confirmation
Contact:Prof. Stuart Croizer, seminar host (stuart@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator)
(guido@itee.uq.edu.au)