Fig 5.

PET imaging with [¹⁸F]FDG and [¹⁸F]PARPi. Tumor-bearing and control mice were injected with an average of 7.7 ± 2.2 MBq (208.1 ± 59.4 µCi) of [¹⁸F]FDG on Day 1 and an average of 10.4 ± 3 MBq (282.2 ± 80.6 µCi) of [¹⁸F]PARPi on Day 2, and imaged under isoflurane anesthesia for 15 minutes, 90 minutes after injection on an INVEON small-animal micro-PET/CT scanner under isoflurane-induced anesthesia. (A) Representative images of the PET/CT scans taken from a tumor-bearing (top row) and a control (bottom row) mouse with the different tracers on consecutive days. Arrows point to the tumor. Images show clear tumor delineation with [¹⁸F]PARPi relative to control. Almost no uptake of the tracer was seen in controls. [¹⁸F]FDG scans showed high physiological uptake in the tongue, floor of mouth, and masticatory muscles in both tumor-bearing and control mice. (B) Quantification of the two tracers in the xenografted and control tongues with [¹⁸F]FDG (first column) and [¹⁸F]PARPi (second). Statistical analysis was performed using the Mann Whitney test in GraphPad Prism 7. Data points represent mean values, and error bars represent standard deviations. [¹⁸F]FDG quantification showed that the uptake in tumor-bearing tongues was not significantly different from the uptake in controls (p > 0.05). [¹⁸F]PARPi quantification showed that the tracer had higher uptake in xenografted tongues when compared to controls (***p < 0.001). [¹⁸F]PARPi-PET allowed delineation of tumor whereas [¹⁸F]FDG failed to do so.