Electricity: measuring and testing – Particle precession resonance – Using a nuclear resonance spectrometer system
Patent
1999-01-25
2000-04-11
Oda, Christine K.
Electricity: measuring and testing
Particle precession resonance
Using a nuclear resonance spectrometer system
324309, 324318, 324322, G01V 300
Patent
active
060492066
ABSTRACT:
This invention relates to a technique for compensating for the inhomogeneity of the field generated by the RF coil (B1) in a nuclear magnetic resonance experiment. Current techniques for achieving accurate flip angles with non-uniform B1 transmit fields, are based upon modulation of the RF waveform. Inherent disadvantages of any RF-based compensation is an increased pulse length and/or increased RF power. Moreover, for some important applications, e.g. multi-slice excitation, no suitable pulses are known. We present an alternative strategy involving a Bz field whose spatial variation is correlated with that of the B1 field. This spatial correlation between the fields allows Bz-based compensation for the effects of B1 inhomogeneity. Successful operation over a wide bandwidth and range of B1 intensities may be achieved without any modification of the RF pulses. An alternative approach for compensating for B1 inhomogeneity is to apply a rapid oscillatory phase-modulation to an existing RF pulse waveform. This approach does not require an additional Bz field, but does not have the minimum RF power advantage of the first approach.
REFERENCES:
patent: 4443760 (1984-04-01), Edelstein et al.
patent: 4471306 (1984-09-01), Edlstein et al.
patent: 4887039 (1989-12-01), Roemer et al.
patent: 5017872 (1991-05-01), Foo et al.
Battison Adrian D.
National Research Council of Canada
Oda Christine K.
Shrivastav Brij B.
Thrift Murray E.
LandOfFree
Compensation for inhomogeneity of the field generated by the RF does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Compensation for inhomogeneity of the field generated by the RF , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compensation for inhomogeneity of the field generated by the RF will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1179450