Mitschang Lorenz
Physikalisch-Technische Bundesanstalt, Division of Medical Physics and Metrological Information Technology, Berlin, Germany.
Magn Reson Med. 2005 May;53(5):1217-22. doi: 10.1002/mrm.20454.
A new adiabatic inversion pulse and its design principles are presented. An analytical expression in the pulse length, inversion bandwidth, inversion efficiency, peak RF amplitude, and width of the transition region is derived and validated. Accordingly, the pulse shape can be adapted to achieve a specified inversion performance. Adjusted for broadband application, population can be inverted band selectively, rather independently of spatial RF field inhomogeneities, and with significantly reduced peak RF amplitude in comparison with the well-known hyperbolic secant adiabatic pulse.
提出了一种新的绝热反转脉冲及其设计原理。推导并验证了脉冲长度、反转带宽、反转效率、射频峰值幅度和过渡区宽度的解析表达式。据此，可调整脉冲形状以实现特定的反转性能。针对宽带应用进行调整后，可选择性地对能带中的粒子数进行反转，相当程度上不受空间射频场不均匀性的影响，并且与著名的双曲正割绝热脉冲相比，射频峰值幅度显著降低。
