pulpy.rf.ptx.stspa

pulpy.rf.ptx.stspa(target, sens, coord, dt, roi=None, alpha=0, b0=None, tseg=None, st=None, phase_update_interval=inf, explicit=False, max_iter=1000, tol=1e-06)[source]
Small tip spatial domain method for multicoil parallel excitation.

Allows for constrained or unconstrained designs.

Parameters:

  • target (array) – desired magnetization profile. [dim dim]

  • sens (array) – sensitivity maps. [Nc dim dim]

  • coord (array) – coordinates for noncartesian trajectories. [Nt 2]

  • dt (float) – hardware sampling dwell time.

  • roi (array) – array for error weighting, specify spatial ROI. [dim dim]

  • alpha (float) – regularization term, if unconstrained.

  • b0 (array) – B0 inhomogeneity map [dim dim]. For explicit matrix building.

  • tseg (None or Dictionary) – parameters for time-segmented off-resonance correction. Parameters are ‘b0’ (array), ‘dt’ (float), ‘lseg’ (int), and ‘n_bins’ (int). Lseg is the number of time segments used, and n_bins is the number of histogram bins.

  • st (None or Dictionary) – ‘subject to’ constraint parameters. Parameters are avg power ‘cNorm’ (float), peak power ‘cMax’ (float), ‘mu’ (float), ‘rhoNorm’ (float), ‘rhoMax’ (float), ‘cgiter’ (int), ‘max_iter’ (int), ‘L’ (list of arrays), ‘c’ (float), ‘rho’ (float), and ‘lam’ (float). These parameters are explained in detail in the SDMM documentation.

  • phase_update_interval (int) – number of iters between exclusive phase updates. If 0, no phase updates performed.

  • explicit (bool) – Use explicit matrix.

  • max_iter (int) – max number of iterations.

  • tol (float) – allowable error.

Returns:

pulses out.

Return type:

array

References

Grissom, W., Yip, C., Zhang, Z., Stenger, V. A., Fessler, J. A. & Noll, D. C.(2006). Spatial Domain Method for the Design of RF Pulses in Multicoil Parallel Excitation. Magnetic resonance in medicine, 56, 620-629.