Simulation of the Sub-Wavelength Focusing Capability of Cylindrical Concave Phased Array

作者全名："Zhou, Yufeng"

作者地址："[Zhou, Yufeng] Chongqing Med Univ, State Key Lab Ultrasound Med & Engn, Coll Biomed Engn, Med Coll Rd, Chongqing 400010, Peoples R China"

通信作者："Zhou, YF (通讯作者)，Chongqing Med Univ, State Key Lab Ultrasound Med & Engn, Coll Biomed Engn, Med Coll Rd, Chongqing 400010, Peoples R China."

来源：JOURNAL OF MEDICAL AND BIOLOGICAL ENGINEERING

ESI学科分类：MOLECULAR BIOLOGY & GENETICS

WOS号：WOS:000836073600001

JCR分区：Q3

影响因子：2

年份：2022

卷号：　

期号：　

开始页：　

结束页：　

文献类型：Article; Early Access

关键词：Focused ultrasound; Phased array; Focus shifting; Sub-wavelength focus

摘要："Purpose Focused ultrasound (FUS) is emerging as an effective modality for clinical therapy. The phased array allows fast focus shifting electronically, but such focus shifting distance is quite limited due to the presence of a grating lobe and reduced acoustic pressure at the shifted focus. In addition, a small focus is preferred to enhance the treatment safety and efficacy, especially in neurological applications. However, because of the diffraction limit the size of most of the focal region from a concave transducer cannot be less than a wavelength. Methods In order to enhance the focusing ability (i.e., the acoustic pressure at the focus and the - 6 dB focused beam area) over a large focus shifting distance and reducing the focal size, a cylindrical concave phased array transducer with a large focusing angle was proposed and evaluated numerically. The generated acoustic field was simulated using the k-space pseudospectral method by varying the driving frequency, focusing angle, and focus shifting distance. Results It is found that the fully enclosed cylindrical design (focusing angle of 360 degrees) could achieve high acoustic pressure and small sub-wavelength focused beam (i.e., < 2 mm(2)) simultaneously at the focus shifting up to 40 mm in comparison to those with a small focusing angle (i.e., 90 degrees). Conclusion Such a fully enclosed cylindrical design may result in the FUS application throughout a large region-of-interest with satisfactory and almost consistent focusing abilities. Therefore, the therapeutic safety and efficacy may be improved."

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