Receive coil optimization for an open magnetic particle imaging scanner

Helmholtz-like coil pairs with a radius of 15 cm have the highest sensitivity for the given geometry. Their homogeneity decreases with higher radius, which is both shown in Fig. 4. Arrays of circular coils show very good homogeneity, which further increases with increasing number of coils, but have comparably poor sensitivity in the FOV. D-shaped coils have both decreasing sensitivity and homogeneity with increasing radius. An increasing distance between a D-coil pair increases the homogeneity, but leads to decreasing sensitivity. Nested D-coils can show an improved homogeneity without a loss in sensitivity. Optimized circular and not nested D-shaped coil pairs with a radius of 15 cm were manufactured and the resonance frequency for both geometries was measured to be about 1.9 MHz for the tight and 2.6 MHz for the loose winding technique.