FIGURE 4. Quantification of tumor-to-liver ratios from sequential {gamma}-images of 111In-labeled C225 conjugates. Data are expressed as ratios of tumor-to-liver radioactivity per pixel and presented as mean ± SEM (n = 3). Tumor-to-liver ratios for both PEG-modified C225 conjugates are significantly higher than ratio for C225 without PEG at each time point (P < 0.05).