Fig. 2. Quantitative X-ray fluorescence microscopy of LB, SOD1 aggregates and neuromelanin demonstrate distinct elemental fingerprints. (A–C) Phase contrast and XFM images of a representative LB, SOD1 aggregate, and NM deposit in the SN from the PD brain. (D) Greater average phase change per feature confirmed the distinctive compositional variation compared to surrounding neuropil (NP). (E) Proteinaceous LBs and SOD1 aggregates both had average areas of ∼24 ± 15 μm², while NM granules occupied a larger and more irregular space (160 ± 77 μm²). (F–K) Spatial concentrations (A_mass; as ng cm⁻² from K_α and K_b emission spectra) of K, P, S, Fe, Cu, and Zn contrasted between features and the encircling neuropil matrix. Scale bars = 1 μm. Structures were sampled from 6–7 PD cases with multiple structures sampled from each case where time was allowed. Total structures analysed; nLB = 8, nSOD1 = 23, nNM = 6, nNP = 32, † = removed outlier. Box-plot graphs depict the median and quartile values as the central line and box boundaries. Whiskers represent min to max values. *p < 0.05, **p < 0.01, ***p < 0.001 based on Kruskal–Wallis (two-sided). Representative images from scan IDs fly25 (LB), fly98 (SOD1), and fly62 (NM).