Noninvasive SPECT-CT monitoring of the pharmacokinetics of VVNIS infection in EC xenografts. Mice with subcutaneous EC xenografts were injected intravenously with VVNIS-C or VVNIS-W. On the day of imaging, each mouse was receiving 300 µCi I125. A and B, SPECT/CT fused images of mice bearing ARK-2 (A) or AN3 CA (B) xenografts on day 14 post virus infection. Location of tumor on each mouse is circled. C, Tumor I125 uptake (uCi/ROI) and tumor volume (cm3) in each mouse on day 7, 14, 21 post virus infection.