QUADRUPOLE GRADIENT COIL DESIGN AND OPTIMIZATION - A PRINTED-CIRCUIT BOARD APPROACH

Three different dual-axis quadrupole gradient coils for quantitative h igh resolution MR imaging of small animals, phantoms and specimens wer e designed and built using printed circuit board technology. Numerical optimization of the conductor positions was used to increase the Volu me of 0.4% gradient uniformity by up to a factor of four. In one coil, the volume of 5% gradient uniformity occupied 88% and 83% of the over all diameter and length of the coil, respectively. A systematic error of 0.5% in the wire placement was shown to cause a reduction in the vo lume of 0.4% gradient uniformity by a factor of two, though the region of 5% gradient uniformity was not significantly affected. Heat transf er calculations were used to determine maximum peak and root-mean-squa red currents that could safely be applied to the coils.