Figure 3.

Contrast Ratio comparison with ¹⁸F-FDG and ⁶⁴Cu-liposome tracers. Contrast ratio was defined as (Tumor_Max – Muscle_Mean) / (Tumor_Max + Muscle_Mean) in %ID/cc. Error bars represent SEM. For mice imaged with ¹⁸F-FDG 13 days after implantation and mice imaged 18 hours after injection with ⁶⁴Cu-liposomes, n = 16 tumors, for all other groups, n = 24 tumors. Cohort imaged 13 days after implantation was maintained under anesthesia for the period between injection of ¹⁸F-FDG and imaging, while mice imaged 21 days after implantation were awakened between injection of ¹⁸F-FDG and imaging, resulting in a reduction in the contrast ratio. For the mice that remained under anesthesia during ¹⁸F-FDG image acquisition (13 days after implantation), at the earliest time point, the contrast ratio is higher for images obtained with ¹⁸F-FDG than ⁶⁴Cu-liposomes, but is comparable at the 18 and 24 hour time points. At 48 hours after injection of ⁶⁴Cu-liposomes, tumor contrast ratio was in all cases superior to ¹⁸F-FDG images.