Alexander J. Raaijmakers1, Jan J. W. Lagendijk1, Dennis W. Klomp2, Bob van den Bergen1, Cecilia Possanzini3, Paul R. Harvey3, Cornelis A. van den Berg1
1Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands; 2Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 3MR systems, Philips Healthcare, Best, Netherlands
Conventional RF transmit coils store their energy in the near-field region. This region extends for approximately a quarter of a wavelength, which corresponds to 4 cm at 7T. Many regions of interest for MR imaging are likely to be located outside this 'near-field' region. As an alternative we present a radiative antenna, which radiates its energy away from the source, resulting in more efficient B1+ penetration. At a depth of 10 cm the radiative antenna shows 20% more B1+ in comparison to a stripline antenna for equal power and 60% more B1+ for equal SARmax.