Fig. 4

NIRF imaging of tumor-bearing nude mice (n = 3). a The NIRF images of tumor-bearing nude mice at different times (1, 6, 12, 18 and 24 h) after the injection of ^99mTc-TEx-Cy7. b The NIRF images of tumor-bearing nude mice at different times (1, 6, 12, 18 and 24 h) after the injection of ^99mTc-AEx-Cy7. c Tumor/Muscle ratios at different times after the injection and their comparations (n = 3, **P < 0.01; ***P < 0.001)