System Design of Ultrasonic Image-guided Focused Ultrasound for Blood Brain Barrier disruption

The purpose of this study is to propose the ultrasonic- imaging guided focused ultrasound induced bloodbrain barrier (BBB) disruption system design. This system comprises of a 270-kHz, 80-channel hemispherical ultrasound phased array, RF power amplifier, animal holder, and a clinical used ultrasound imager. Before animal treatment, we propose to use high-precision hydrophone and ultrasound imager coordinate transformation to achieve the alignment, focused ultrasound guidance, and treatment position targeting. During the treatment, Forty Sprague-Dawley rats were sonicated, and burst-mode ultrasonic energy was delivered in the presence of micro bubbles injected IV to disrupt the BBB. All Rats were skull-intact during the sonication, and different power output and duration durations were tested. Evans Blue dye was serves as an indicator to verify the BBB disruption in gross animal sectioning, and hematoxylin and eosin (H&E) staining was conducted for brain tissue damage analysis. Results showed that the designed hemispherical multiple channel phased array system under the ultrasonic imaging guidance can successfully disrupt BBB through intact skull at the targeting position. Safety parameter was characterized which ranges from 5 - 7.5 w of electrical power with the sonication duration of 30 - 180 s. The design provides the possibility toward using ultrasonic imaging to guide the focused ultrasound induced BBB disruption process for targeting drug delivery.