Fig. 3
Correlated MALDI MS imaging of the drug (erlotinib) distribution and SRS imaging of the brain tissue morphology. a MALDI MS ion imaging shows the distribution of Erlotinib across the entire brain tissue section. b SRS imaging shows the chemical constituents (lipid in green; protein in blue; and heme in red) of the entire serial brain tissue section. c H&E image of another serial brain tissue section corresponding to a and b. d Enlarged overlaid view of areas marked by the large rectangle in a and b shows distribution of the drug (erlotinib in pink) and tissue morphology (lipid and protein in green and blue, respectively) of the tumor area, e H&E image corresponding to d. f Enlarged overlaid images of the tumor margin area (marked by rectangle in d) shows cancer cell invasion into the normal fatty brain structure. g H&E image corresponding to f. h Enlarged overlaid images of the brain structure (marked by smaller rectangle on a and b featuring the difference between gray (protein rich—blue) and white (lipid rich—green) matter. High concentration of erlotinib was found in the third ventricle h, with corresponding H&E image shown in i. Scalebars represent lengths as follows: a–c = 1 mm, d and e = 500 µm, f–i = 200 µm
