High resolution LA-ICP-MSI distribution analysis of photodynamic therapy drugs (CuPc, ZnPc, and CoTsPc) in the small intestine of mouse after oral administration. Left panel shows the optical image of the intestine slice and the MS images of 59Co, 63Cu and 67Zn distribution in a same intestine slice with spatial resolutions at 10, 1, and 0.5 μm/pixel. Images (a-c) in the left panel are MSI of Co, Cu and Zn of the small intestine at 10 μm/pixel. Images (j-l) are MSI of Co, Cu and Zn of the red region outlined in the optic image of the small intestine at 1 μm/pixel. Images (m-o) are MSI of Co, Cu and Zn of the yellow region outlined in the optic image of the small intestine at 0.5 μm/pixel. The right panel shows the zoomed-in MS image of the intestine to identify the cells within the intestine at different spatial resolutions (0.5, 1 and 2 μm/pixel). Printed with permission from [60]. Copyright 2022, ACS.