Design of a forward view antenna for prostate imaging at 7T

• Published in: NMR in biomedicine 2018-09, Vol.31 (9)
• Main Authors: Steensma, Bart R, Voogt, Ingmar, Abe J van der Werf, Cornelis AT van den Berg, Luijten, Peter R, Klomp, Dennis WJ, Raaijmakers, Alexander JE
• Format: Article
• Language: English
• Subjects: Antenna arrays; Biological products; Computer simulation; Design; Dipole antennas; Dipoles; Mathematical models; Prostate; Rectangular waveguides; Simulation; Wave propagation
• ISSN: 0952-3480; 1099-1492
• DOI: 10.1002/nbm.3993

PurposeTo design a forward view antenna for prostate imaging at 7 T, which is placed between the legs of the subject in addition to a dipole array.Materials and methodsThe forward view antenna is realized by placing a cross‐dipole antenna at the end of a small rectangular waveguide. Quadrature drive of the cross‐dipole can excite a circularly polarized wave propagating along the axial direction to and from the prostate region. Functioning of the forward view antenna is validated by comparing measurements and simulations. Antenna performance is evaluated by numerical simulations and measurements at 7 T.ResultsSimulations of B1+ on a phantom are in good correspondence with measurements. Simulations on a human model indicate that the signal‐to‐noise ratio (SNR), specific absorption rate (SAR) efficiency and SAR increase when adding the forward view antenna to a previously published dipole array. The SNR increases by up to 18% when adding the forward view antenna as a receive antenna to an eight‐channel dipole array in vivo.ConclusionsA design for a forward view antenna is presented and evaluated. SNR improvements up to 18% are demonstrated when adding the forward view antenna to a dipole array.