selective excitation

selective excitation

An MRI term for controlling the frequency spectrum (bandwidth) of a radio frequency excitation pulse while imposing a gradient magnetic field on spins, so that only a desired region will have a suitable resonant frequency to be excited.
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References in periodicals archive ?
Suryanarayana, "Effect of [sup.87]Sr hyperfine structure on the isotope selective excitation of 89Sr and [sup.90]Sr isotopes in collinear resonance ionization spectroscopy," Journal of Physics B: Atomic, Molecular and Optical Physics, vol.
Frydman, "Longitudinal relaxation enhancement in 1H NMR spectroscopy of tissue metabolites via spectrally selective excitation," Chemistry, vol.
Macovski, "Parameter relations for the Shinnar-Le Roux selective excitation pulse design algorithm [NMR imaging," IEEE Trans.
In recent years some works have been done in the investigation of these waves broadband excitation using piezoelectric wafer active sensors (PWAS) [4]-[9], evaluating such factors as the size of the element, selective excitation and mode control schemes which are basically used in SHM applications.
PANalytical says the performance of the Epsilon 3 comes from selective excitation and careful matching of the x-ray tube output to the capabilities of the detection system, together with "advanced spectrum processing and unique correction and quantification algorithms".
For those sequences for which SAR does affect the pulse sequence, other solutions may be applied, including parallel imaging to shorten echo trains (with a small reduction in optimal SNR), (9-11) and tailored RF pulse shapes or flip angles (variable-rate selective excitation, hyperecho-turbo spin-echo, transition between pseudo steady-states).
Hence, the KR illumination leads to a strong selective excitation in close proximity to the metal surface.

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