Quantitative PET ROI and BioD analysis of ⁸⁹Zr-DFO-ICOS mAb in acute GvHD. (A) Quantitative ROI analysis of PET images (upper panels) and BioD (lower panels) of spleen, mLN, intestine, liver, heart, kidney, bone, and muscle 48 hours after tracer injection in TBI (blue; n = 5), BM (green; n = 7), or GvHD mice (red; n = 11). Values are summarized as box plots, representing the range, first quartile, median, third quartile, and eventual outliers. Tracer uptake in GvHD and TBI or BM mice was compared using the Mann-Whitney U test. (B) Correlation between tracer uptake measured by PET ROI image analysis with that determined by BioD analysis, evaluated using a Spearman rank correlation coefficient test. Results are pooled from 2 independent experiments. %ID/g, percent injected dose per gram.