| Autor: |
Budé, Lyanne M. I., Steensma, Bart R., Zivkovic, Irena, Raaijmakers, Alexander J. E. |
| Předmět: |
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| Zdroj: |
Magnetic Resonance in Medicine; Jul2024, Vol. 92 Issue 1, p361-373, 13p |
| Abstrakt: |
Purpose: The coax monopole antenna is presented for body imaging at 7 T. The antenna is fed at one end, eliminating the possibility of cable‐coil coupling and simplifying cable routing. Additionally, its flexibility improves loading to the subject. Methods: Like the coax dipole antenna, an interruption in the shield of the coaxial cable allows the current to extend to the outside of the shield, generating a B1+ field. Matching is achieved using a single inductor at the distal side, and a cable trap enforces the desired antenna length. Finite difference time domain simulations are employed to optimize the design parameters. Phantom measurements are conducted to determine the antenna's B1+ efficiency and to find the S‐parameters in straight and bent positions. Eight‐channel simulations and measurements are performed for prostate imaging. Results: The optimal configuration is a length of 360 mm with a gap position of 40 mm. Simulation data show higher B1+ levels for the coax monopole (20% in the prostate), albeit with a 5% lower specific absorbance rate efficiency, compared to the fractionated dipole antenna. The S11 of the coax monopole exhibits remarkable robustness to loading changes. In vivo prostate imaging demonstrates B1+ levels of 10–14 μT with an input power of 8 × 800 W, which is comparable to the fractionated dipole antenna. High‐quality images and acceptable coupling levels were achieved. Conclusion: The coax monopole is a novel, flexible antenna for body imaging at 7 T. Its simple design incorporates a single inductor at the distal side to achieve matching, and one‐sided feeding greatly simplifies cable routing. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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