Method and apparatus for obtaining N.M.R. spectra and coils for use therein
AssigneeOxford Research Systems Limited
InventorsMax R. Bendall, Jamie M. McKendry
Life of this patent
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Abstract
Use of a switch at the end of a .lambda./4 cable inserted between the Rf coil and ground allows the coil to be tuned and detuned at will. This detune switch essentially eliminates coupling between adjacent coils permitting operation of multiple transmit coils at the same frequency. These switches have been employed to prove a previously proposed method of complete sensitive-volume localization using multiple Rf coils and depth pulse schemes. The example illustrated is the case of two coaxial coplanar surface coils. There are important uses in in-vivo spectroscopy.
Claims11
Apparatus for obtaining an N.M.R. spectrum of a sample, which apparatus comprises;
- means for generating a static magnetic field;
- a sample location space within the magnetic field for containing the sample;
- means for applying to the space an Rf field having a wavelength such as to cause perturbation of nuclear spins in the sample space in the presence of the magnetic field;
- means for detecting the Rf signal induced in the sample as a consequence of the applied rf field, the apparatus comprising at least two tuned Rf coils, at least one of the said Rf coils being connected to ground via a selectively operable high speed switch, whereby operation of the switch causes the detuning of the said at least one coil and thereby the decoupling of the said coil from the said other coil;
- said apparatus further comprising processing means for controlling the high-speed switch to cause said detuning.
A coil assembly for use in an N.M.R. spectrometer, comprising at least two pairs of complimentary electrical coils, the coils of each pair being inclined with respect to each other in a `flower-petal` configuration about an axis of symmetry, with coils corresponding to diametrically opposite petals connected together such that the same electrical current flows in diametrically opposed coils, and wherein the assembly further comprises an additional coil, said additional coil being disposed in a plane substantially perpendicular to said axis of symmetry.
Dependencies are inferred from the claim text.