Focused beam control for ultrasound surgery with spherical-section phased array: sound field calculation and genetic optimization algorithm

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 52; no. 8; pp. 1270 - 1290
• Main Authors: Lu, Mingzhu, Wan, Mingxi, Xu, Feng, Wang, Xiaodong, Zhong, Hui
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.08.2005; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Acoustic beams; Acoustics; Algorithms; Animals; Applicators; Biological and medical sciences; Biomedical engineering; Computer Simulation; Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Exact sciences and technology; Fundamental areas of phenomenology (including applications); General equipment and techniques; Genetic algorithms; Genetics; Humans; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Investigative techniques, diagnostic techniques (general aspects); Mathematical analysis; Medical sciences; Miscellaneous. Technology; Models, Genetic; Neoplasms; Optimization; Optimization methods; Phased arrays; Physics; Scattering, Radiation; Sound fields; Strategy; Surgery; Surgery, Computer-Assisted - instrumentation; Surgery, Computer-Assisted - methods; Testing; Therapy, Computer-Assisted - methods; Transducers; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonic Therapy - instrumentation; Ultrasonic Therapy - methods; Ultrasonics, quantum acoustics, and physical effects of sound; Human; Phased array; Spherical antenna; Acoustic beam; Experimental study; Modeling; Optimization; Genetic algorithm; Surgery; Focusing; Feasibility; Acoustic antenna; Ultrasonic transducer; Point source
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2005.1509786

This study aims at a sound field calculation for the spherical-section phased array and an optimization algorithm for the focus patterns of phased array ultrasound surgery. An efficient field calculation formula represented as an explicit expression is derived by the strategies of projection and binomial expansion. An optimization algorithm based on genetic algorithm is constructed by the suitable fitness function and the selection strategies. The simulation results of 256-element spherical-section phased array show the capability of controlling focus accurately and effectively with the combined method made up of the explicit expression method and the genetic optimization algorithm. The simulation results of single focus, multiple foci, on-axial focus, and off-axial focus further convince the feasibility of three-dimensional (3-D) focus steering with excellent acoustic performances. A single focus with the focus dimension of 1.25 mm /spl times/ 1.25 mm /spl times/ 7 mm and with the intensity of 6080 W/cm/sup 2/ is formed. The multiple-focus pattern can enlarge the treatment volume 22 times larger than that of single focus with a sonication. In addition, a comparison between the explicit expression approach and the point source approach testifies to the applicability of the explicit expression approach. The experiment and simulation results of 16-element array actually confirm the feasibility of the combined method.