Figure 1.

VCAM-MPIO showed tumor uptake and a fast distribution phase. (A) Maximum intensity projection of PET data 5 and 45 minutes after infusion of ⁶⁸Ga-IgG-MPIO control particles. Particles accumulated in the liver and spleen without appreciable uptake in EL4 tumors (black arrows) (B) Maximum intensity projection 5 and 45 minutes after ⁶⁸Ga-VCAM-MPIO particle infusion showed high uptake in the liver, spleen, and lymph nodes in EL4 tumors. (C) Quantification of specific uptake in liver, spleen, tumor, and heart (surrogate for blood pool) during the first 45 minutes following ⁶⁸Ga-IgG-MPIO (n = 4 mice) or (D)⁶⁸Ga-VCAM-MPIO (n = 6 mice) infusion. (E) VCAM-MPIO showed tumor specific uptake (3% ID/g) while IgG-MPIO increased initially but returned to less than 0.5% ID/g 5 minutes after infusion. ***P < .01 one-way-ANOVA. Data are shown as mean ± SD.