Simulations of high permittivity materials for 7 T neuroimaging and evaluation of a new barium titanate‐based dielectric
Citations Over TimeTop 10% of 2012 papers
Abstract
High permittivity "dielectric pads" have been shown to increase image quality at high magnetic fields in regions of low radiofrequency transmit efficiency. This article presents a series of electromagnetic simulations to determine the effects of pad size and geometry, relative permittivity value, as well as thickness on the transmit radiofrequency fields for neuroimaging at 7 T. For a 5-mm thick pad, there is virtually no effect on the transmit field for relative permittivity values lower than ∼90. Significant improvements are found for values between 90 and ∼180. If the relative permittivity is increased above ∼180 then areas of very low transmit efficiency are produced. For a 1-cm thick pad, the corresponding numbers are ∼60 and ∼120, respectively. Based upon the findings, a new material (barium titanate, relative permittivity ∼150) is used to produce thin (∼5 mm) dielectric pads which can easily be placed within a standard receive head array. Experimental measurements of transmit sensitivities, as well as acquisition of T(2) - and T 2*-weighted images show the promise of this approach.
Related Papers
- → Simulations of high permittivity materials for 7 T neuroimaging and evaluation of a new barium titanate‐based dielectric(2012)142 cited
- → Compact pulse forming line using barium titanate ceramic material(2011)16 cited
- → Dielectric permittivity calculation of composites based on electrospun barium titanate fibers(2015)8 cited
- → Dielectric Residual Effects in Titanates(1947)2 cited
- → Automatic Determination of the Complex Permittivity of Liquids of Low Dielectric Loss(1985)1 cited