PGP and neoplasm: FDG, FLT, [11C]Methionine and [18F]fluoroazomycin-arabinofuranoside ([18F]FAZA) are suitable PET tracers for the diagnosis and in vivo follow-up of the efficacy of tumor chemotherapy (doxorubicin) in both Pgp(+) and Pgp(−) human tumor xenografts by mini PET