High Frequency Mri Rf Coil Design

Open Access
Author:
Zhang, Haolun
Graduate Program:
Engineering Science and Mechanics
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 01, 2013
Committee Members:
  • Michael T Lanagan, Thesis Advisor
  • Thomas Neuberger, Thesis Advisor
  • Jian Xu, Thesis Advisor
Keywords:
  • high frequency
  • mri
  • rf coil
Abstract:
MRI is one of the major imaging techniques in the daily clinical routine. A major trend in clinical and research MRI systems is the increase in resolution through using higher static magnetic fields. The static B_0 magnetic field strength of clinical scanners ranges from 0.5 to 3 T, and the corresponding RF signal frequencies (proportional to the magnetic field,B_1) for protons are 21 MHz and 128 MHz, respectively. Penn State has a 14T and 20T system with operating proton frequencies of 600 MHz and 850 MHz, respectively. By moving toward the higher frequencies, the design of MRI detectors called RF resonators become more challenging. In this work RF resonators for high-field MRI applications operating at 600 MHz and 850 MHz are designed and constructed. Simulations using a commercial finite-difference-time-domain code CST (Computer Simulation Technology) are acquired to get the circuit capacitance values and the B_1 field generated coil. RF resonators are comprised of capacitors and inductive coils. The capacitors provide matching and tuning functions so that the resonant frequency of the loaded coil remains at the Larmor frequency of 600MHz and 850 MHz. The coils are used for imaging after they are successfully fabricated.