3. Results
3.1. Rat model of tumor and inflammation
The volume of 9L tumors in Fisher 344 female rats was variable: Tumor mass at radiotracer injection was 1.43±0.86 g (mean±S.D.). Tumor diameter reached 1–1.5 cm on 14 days after 9L injection, and E. coli injection resulted in swelling of left thigh muscle after 24 h.
3.2. The change of [18F]-FLT biodistribution by pretreatment of thymidine phosphorylase
To reduce Batimastat serum levels of endogenous thymidine, rats were pretreated with TP in [18F]-FLT biodistribution (Table 1). Blood clearance of [18F]-FLT was markedly retarded by TP pretreatment (with TP, 0.35±0.10 %ID/g; without TP 0.14±0.01 %ID/g at 60 min). The TP-pretreated group showed approximately two times higher [18F]-FLT uptake in tissues than the TP-nontreated group, except femur, pancreas and inflammation. [18F]-FLT uptake of femur and inflammation in the TP-pretreated group was 6.9 and 3.9 times, respectively (P.05).