Design and Testing of a Radiofrequency Ellipsoidal Helmholtz Coil in Contrast with a Circular Pair for Nuclear Magnetic Resonance
Received: 11 April 2023 | Revised: 27 April 2023 | Accepted: 5 May 2023 | Online: 2 June 2023
Corresponding author: Khalid Al-Snaie
Abstract
The design and testing of a Helmholtz prototype probe with a relatively homogeneous radiofrequency field that can be used for MRI are presented in this paper. It consists of two coaxial separately tuned ellipsoidal rings of wire in a symmetric arrangement. The developed ellipsoidal structure is tested experimentally in free space and is compared with the results obtained with an equivalent circular standard Helmholtz coil. Complete electrical modeling of the coils taking into account all couplings (inductive and capacitive) is studied. The proposed ellipsoidal Helmholtz coil provides better performance in terms of field homogeneity, efficiency, and quality factor. The width of the lobe at 10% for the ellipsoidal coil is 20% bigger. Moreover, a significant improvement in the quality factor is observed in free space. Also, the efficiency is increased by 37%. Finally, the Signal to Noise Ratio (SNR) of the ellipsoidal coil is higher than that of the circular coil.
Keywords:
MRI, NMR, radio frequency, RF coil, ellipsoidal configuration, B1 homogeneityDownloads
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