Figure 5. Accumulation of ⁸⁹Zr-cRGD-C’ dots in mGBM and rapid systemic clearance.

a) Representative maximum projected intensity PET image of a mGBM mouse treated with ⁸⁹Zr-cRGD-C’ dots. Images were acquired at 0.5 hours (top row) and 24 hours (bottom row) after intravenous particle injection. Accumulation of ⁸⁹Zr-cRGD-C’ dot in the brain was measured to be ~7% ID/g. b) Histological analysis of whole brain extracted from mouse in Figure 5a, showing H&E confirmation of tumor and particle distribution demonstrated by optical (Cy5) and autoradographic (⁸⁹Zr) imaging. c) Histological analysis of 5 mice treated with intravenous ⁸⁹Zr-cRGD-C’ dots (72 hours post-injection) illustrating tumor (H&E) and particle localization (Cy5 and autoradiography; scale bars= 1 mm). d) Analysis of average autoradiography signal intensity as a function of overall tumor area demonstrates a positive correlation (R² = 0.6474). e) Tumor to normal brain analysis of mice from Figure 5c demonstrating a >150-fold increase in ⁸⁹Zr-cRGD-C’ dot accumulation in tumor as compared to surrounding normal brain (Tumor = 164.713, Normal = 1.1364; Student’s t test, ** p = 0.0029).