Fig. 5: Reconstructed images of performed magnetic particle imaging measurements of magnetic hydrogels in different pH solutions.

First row: samples in dry state, second row: same samples in swollen state. Images in (a) are reconstructed with three system matrices with multi-color mapping with red pH 2 channel, green pH 4 and blue pH 7 channel. Images in (b) are reconstructed with two system matrices for pH 2 and 7. (c) shows maximum intensity projections of (b) with calculated full-width at half-maximum values.