Use of Amplitude and Frequency Transformations to Generate Adiabatic Pulses of Wide Bandwidth and Low RF Power Deposition

Abstract

An amplitude transformation of adiabatic pulses stated previously [Baumet al., Phys. Rev. A32, 3435–3447 (1985)] is generalized using the Bloch equations. Both amplitude and frequency transformations are used to create new adiabatic pulses of wide bandwidth and low RF power deposition. Several adiabatic pulses (including the tanh/tan pulse used for construction of BIR-4, SSAP, and BISEP pulses) are transformed into new pulses. These new pulses are demonstrated numerically and experimentally to operate at a significantly lower RF power level while maintaining the same performance or over a wider bandwidth while using the same RF power. They are expected to be useful forin vivoNMR experiments, especially for applications involving wide frequency dispersion and pulse sequences composed of many adiabatic half-passage pulses.