Unlike NMR imaging, where only the components of the magnetic field gradients along the main applied field need be considered, all nonzero components of the gradients must be considered for NQR imaging of powder or polycrystalline materials. Any physically realizable gradient coil will have at least two nonzero components. Since the nonzero components are of comparable magnitude, image reconstruction will not be as straightforward as is found for NMR imaging. Here a practical NQR imaging reconstruction technique based on the use of standard techniques but using a nonrectilinear grid is demonstracted for physically realizable gradients. A two-dimensional image constructed using the 35Cl NQR signal from a polycrystalline sample of NaClO3 is presented to demonstrate the technique.
Journal of Magnetic Resonance, Vol 138, pg 123 (1999).