Figure 1. Conceptual diagrams of focused ultrasound induced blood-brain barrier opening to enhance chemotherapeutic agent delivery for brain tumor treatment.

(a) Focused ultrasound is used to transcranially steer the exposure to the targeted brain tumor region; (b) focused ultrasound induces a local and reversible increase in BBB permeability of tight junctions in cerebral vessels and capillaries in the tumor core/ peripheral region. EC = endothelial cell, N = neuron, P = pericytes, A = astrocyte, D = chemotherapeutic agent, MB = microbubble.