Research Article Open Access

A HIGH B1 FIELD HOMOGENEITY GENERATION USING FREE ELEMENT ELLIPTICAL FOUR-COIL SYSTEM

Sidi M. Ahmed Ghaly1 and Sulaiman S. Al-Sowayan1
  • 1 Al Imam Muhammad Ibn Saud Islamic University (IMSIU), Saudi Arabia
American Journal of Applied Sciences
Volume 11 No. 4, 2014, 534-540

DOI: https://doi.org/10.3844/ajassp.2014.534.540

Submitted On: 26 December 2013 Published On: 28 January 2014

How to Cite: Ghaly, S. M. A. & Al-Sowayan, S. S. (2014). A HIGH B1 FIELD HOMOGENEITY GENERATION USING FREE ELEMENT ELLIPTICAL FOUR-COIL SYSTEM. American Journal of Applied Sciences, 11(4), 534-540. https://doi.org/10.3844/ajassp.2014.534.540

Abstract

Design and testing of a prototype probe with high B1 magnetic field homogeneity that can be used for MRI is presented. It consists of four coaxial separately tuned rings of wire in a symmetric arrangement on an ellipsoidal surface. Compared to Helmholtz pair, which presents 2nd-order homogeneity, an improvement in field homogeneity is achieved, while preserving the simplicity of implementation. The proposed probe has an identical self-resonance frequency for all coils to allow easy tuning. The position and diameter of each ring are optimized so that the assembly produces a 6th-order homogeneous field. A complete electrical model of the four-coil system taking into account all coupling effects permits to determine the resonance frequency in the co-current mode and consequently to predict the value of the tuning capacitors. Resulted field homogeneity of the proposed four-coils are compared to that of Helmholtz coil which shows an improvement of 58% in field homogeneity profile when considering 10% profile uniformity width. Moreover, compared to the homologous Helmholtz coil, the proposed four-coil prototype possesses a better quality factor and therefore leads to an improved Nuclear Magnetic Resonance (NMR) sensitivity.

  • 790 Views
  • 2,122 Downloads
  • 3 Citations

Download

Keywords

  • Magnetic Flux Density
  • Field Homogeneity
  • Helmholtz Coil