PGP and brain neoplasm: P-gp was shown to fully recover three days after FUS application at low AP (e.g., peak negative pressure—PNP of 0.5 MPa, in situ) [23,24] whereas, at a higher AP of 0.8 MPa (similar to levels used in brain tumors trials [25,26]), P-gp does not return to baseline after three days [24].