Diverging Polymer Acoustic Lens Design for High-Resolution Row-Column Array Ultrasound Transducers

作     者：Audoin, Melanie Salari, Ali Tomov, Borislav Gueorguiev Pedersen, Kasper Flong Jensen, Jorgen Arendt Thomsen, Erik Vilain 

作者机构：Tech Univ Denmark Dept Hlth Technol DK-2800 Kongens Lyngby Denmark 

出 版 物：《IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL》 (IEEE Trans Ultrason Ferroelectr Freq Control)

年 卷 期：2024年第71卷第1期

页      面：202-213页

核心收录：

学科分类：0808[工学-电气工程] 08[工学] 0702[理学-物理学] 

基　　金：European Research Council's (ERC) Synergy 

主　　题：Acoustic lens field of view (FOV) medical imaging row-column array ultrasound transducer 

摘      要：Spherical diverging acoustic lenses mounted on flat 2-D row-column-addressed (RCA) ultrasound transducers have shown the potential to extend the field of view (FOV) from a rectilinear to a curvilinear volume region and, thereby, enable 3-D imaging of large organs. Such lenses are usually designed for small aperture low-frequency transducers, which have limited resolution. Moreover, they are made of off-the-shelf pieces of materials, which leaves no room for optimization. We hypothesize that acoustic lenses can be designed to fit high-resolution transducers, and they can be fabricated in a fast, cost-effective, and flexible manner using a combination of 3-D printing and casting or computer numerical control (CNC) machining techniques. These lenses should increase the FOV of the array while preserving the image quality. In this work, such lenses are made in concave, convex, and compound spherical shapes and from thermoplastics and thermosetting polymers. Polymethylpentene (TPX), polystyrene (PS), polypropylene (PP), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), and room-temperature vulcanizing (RTV) silicone diverging lenses have been fabricated and mounted on a 128 + 128 6-MHz RCA transducer. The performances of the lenses have been assessed and compared in terms of FOV, signal-to-noise ratio (SNR), bandwidth, and potential artifacts. The largest FOV (24.0 degrees) is obtained with a 42.64-mm radius PMMA-RTV compound lens, which maintains a decent fractional bandwidth (53%) and SNR at 6 MHz (-9.1-dB amplitude drop compared with the unlensed transducer). The simple PMMA TPX, PS, PP, PDMS, and RTV lenses provide an FOV of 12.2 degrees, 6.3 degrees, 8.1 degrees, 11.7 degrees, 0.6 degrees, and 10.4 degrees;a fractional bandwidth of 97%, 46%, 103%, 46%, 97%, 53%, and 49%;and an amplitude drop of -5.2, -4.4, -2.8, -15.4, -6.0, and -1.8 dB, respectively. This work demonstrates that thermoplastics are suitable materials for fabricating low-attenuation convex d