P-Glycoprotein Function at the Blood–Brain Barrier in Humans Can Be Quantified with the Substrate Radiotracer ¹¹C-<i>N-Desmethyl</i>-Loperamide

Abstract

P-gp function at the blood-brain barrier in humans can be quantified using PET and (11)C-dLop. A simple measure of brain uptake (AUC(10-30)) may be used as a surrogate of the fully quantified rate constant for brain entry (K(1)) and thereby avoid arterial sampling. However, to dissect the function of P-gp itself, both brain uptake and the influx rate constant must be corrected for radiotracer delivery (blood flow).