Molecular Imaging of ABCB1 and ABCG2 Inhibition at the Human Blood–Brain Barrier Using Elacridar and 11C-Erlotinib PET

C-erlotinib was not higher after administration of elacridar. The more pronounced role that ABCG2 appears to play at the human blood-brain barrier and the lower potency of elacridar to inhibit ABCG2 may be an explanation of these interspecies differences.