Focused ultrasound enhanced intranasal drug delivery (IN+FUS) is a unique noninvasive approach that utilizes the olfactory pathway to administer drugs directly to the brain. Our group has shown that IN+FUS provides a more homogenous distribution of molecules in the targeted region than intranasal delivery alone. The underlying mechanism of IN+FUS is believed to be due to the microbubble pump effect, where microbubble cavitation causes expansion and contraction of the perivascular space. Therefore, the aim of this study is to investigate a potential cavitation threshold that is required for successful IN+FUS.