PGP and neoplasm: This study revealed enhanced uptake of 99mTc MIBI in NSCLC cells in vitro after 6- and 9-Gy irradiation, and an extended intracellular doxorubicin residence time in in vivo xenografted NSCLC tumours at 48 h after 9-Gy irradiation, although there was no difference in the expression of Pgp and BCRP between cells before and after 9-Gy irradiation immunocytochemically.