A METHOD OF PRODUCING HIGH-QUALITY LINEAR FIELD GRADIENT FOR MAGNETIC-RESONANCE-IMAGING USING STRAIGHT CURRENT LINES

A new method for generating a highly linear field gradient in a large space is described. The coil system consists of N equispaced parallel current lines placed on a cylinder perpendicular to the static magnetic field. The wires generate a gradient of any accuracy depending on N and in any direction in a plane perpendicular to the cylinder axis by controlling the current of each wire independently. The accuracy of the gradient using 16 infinite-length wires is less than 0.3% in the 60% region in diameter of the cylinder. An ESR-CT image of a DPPH test sample was obtained using this system of 16 wires.