scholarly journals Geometric Optimal Control of the Contrast Imaging Problem in Nuclear Magnetic Resonance

2012 ◽  
Vol 57 (8) ◽  
pp. 1957-1969 ◽  
Author(s):  
B. Bonnard ◽  
O. Cots ◽  
S. J. Glaser ◽  
M. Lapert ◽  
D. Sugny ◽  
...  
2012 ◽  
Vol 2012 ◽  
pp. 1-29 ◽  
Author(s):  
Bernard Bonnard ◽  
Steffen J. Glaser ◽  
Dominique Sugny

We present a geometric framework to analyze optimal control problems of uncoupled spin 1/2 particles occurring in nuclear magnetic resonance. According to the Pontryagin's maximum principle, the optimal trajectories are solutions of a pseudo-Hamiltonian system. This computation is completed by sufficient optimality conditions based on the concept of conjugate points related to Lagrangian singularities. This approach is applied to analyze two relevant optimal control issues in NMR: the saturation control problem, that is, the problem of steering in minimum time a single spin 1/2 particle from the equilibrium point to the zero magnetization vector, and the contrast imaging problem. The analysis is completed by numerical computations and experimental results.


2013 ◽  
Vol 3 (4) ◽  
pp. 375-396 ◽  
Author(s):  
Elie Assémat ◽  
◽  
Marc Lapert ◽  
Dominique Sugny ◽  
Steffen J. Glaser ◽  
...  

2013 ◽  
Vol 3 (4) ◽  
pp. 397-432 ◽  
Author(s):  
Bernard Bonnard ◽  
◽  
Monique Chyba ◽  
Alain Jacquemard ◽  
John Marriott ◽  
...  

2012 ◽  
Vol 405 ◽  
pp. 71-75 ◽  
Author(s):  
E. Assémat ◽  
L. Attar ◽  
M.-J. Penouilh ◽  
M. Picquet ◽  
A. Tabard ◽  
...  

2013 ◽  
Vol 24 (01) ◽  
pp. 187-212 ◽  
Author(s):  
B. BONNARD ◽  
O. COTS

The purpose of this paper is to present numerical methods and results about the contrast imaging problem in nuclear magnetic resonance which corresponds to a Mayer problem in optimal control. The candidates as minimizers are selected among a set of extremals, solutions of a Hamiltonian system given by the Pontryagin Maximum Principle and sufficient second order conditions are described. They form the geometric foundations of the HAMPATH code which combines shooting and continuation methods, see Ref. 9. The main contribution of this paper is to present a numerical analysis of the contrast imaging problem in NMR in the case of deoxygenated/oxygenated blood samples as an application of the aforementioned techniques.


2014 ◽  
Vol 543-547 ◽  
pp. 2288-2291
Author(s):  
Shu Lin Zhang ◽  
Yan Chang ◽  
Xiao Dong Yang

In this paper, we introduce an optimal control theory (OCT) based method for design of broadband excitation pulse with limited radio frequency (RF) amplitude in nuclear magnetic resonance (NMR). The capability of the optimized pulse was verified by the following design criteria: the state transfer of 1H fromtoover resonance offsets of, the pulse duration is 1ms with maximum RF amplitude of 10 kHz. The simulation result demonstrates that the optimal control-based shaped pulse is much more adaptable to broadband excitation, providing a better performance than traditional hard pulse.


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