Figure 4. In-vivo metabolism of wild-type [¹⁸F]FB-IL2 and mutant [¹⁸F]FB-IL2v in Wistar rats, as determined by the TCA precipitation assay.

(A) Blood samples were collected at different time points after tracer injection. Plasma was collected and subjected to the TCA precipitation assay and the percentage of intact tracer was determined. (B) Urine was collected from the bladder 80 min after mutant [¹⁸F]FB-IL2v injection and the percentage of intact labelled protein was determined by means of the precipitation TCA assay.