Design and Implementation of a Transmit/Receive Ultrasound Phased Array for Brain Applications

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 65; no. 10; pp. 1756 - 1767
• Main Authors: Liu, Hao-Li, Tsai, Chih-Hung, Jan, Chen-Kai, Chang, Hsin-Yu, Huang, Sheng-Min, Li, Meng-Lin, Qiu, Weibao, Zheng, Hairong
• Format: Journal Article
• Language: English
• Published: United States IEEE 01-10-2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic beams; Acoustics; Backscattering; Beamforming; Blood–brain barrier (BBB) opening; Brain; Channels; coherent beam formation; dual transmit/receive mode; Energy transmission; Field programmable gate arrays; Image reconstruction; Phased arrays; Point spread functions; Pressure distribution; Radio frequency; Real time; Stress concentration; Systems design; transcranial brain therapy; Ultrasonic imaging; Ultrasonic testing; Ultrasound; ultrasound phased array
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2018.2855181

Focused ultrasound phased array systems have attracted increased attention for brain therapy applications. However, such systems currently lack a direct and real-time method to intraoperatively monitor ultrasound pressure distribution for securing treatment. This study proposes a dual-mode ultrasound phased array system design to support transmit/receive operations for concurrent ultrasound exposure and backscattered focal beam reconstruction through a spherically focused ultrasound array. A 256-channel ultrasound transmission system was used to transmit focused ultrasonic energy (full 256 channels), with an extended implementation of multiple-channel receiving function (up to 64 channels) using the same 256-channel ultrasound array. A coherent backscatter-received beam formation algorithm was implemented to map the point spread function (PSF) and focal beam distribution under a free-field/transcranial environment setup, with the backscattering generated from a strong scatterer (a point reflector or a microbubble-perfused tube) or a weakly scattered tissue-mimicking graphite phantom. Our results showed that PSF and focal beam can be successfully reconstructed and visualized in free-field conditions and can also be transcranially reconstructed following skull-induced aberration correction. In vivo experiments were conducted to demonstrate its capability to preoperatively and semiquantitatively map a focal beam to guide blood-brain barrier opening. The proposed system may have potential for real-time guidance of ultrasound brain intervention, and may facilitate the design of a dual-mode ultrasound phased array for brain therapeutic applications.