Mitra Mahaan, Kumar Akshay, Khandare Shubham, Gaddale Prameth, Anandan Yashoda, Pedibhotla Srian, Roy Kaustav, Chen Haoyang, Pratap Rudra, Kothapalli Sri-Rajasekhar
Department of Biomedical Engineering, Pennsylvania State University, University Park, State College, PA 16802, USA.
Centre for Nano Science and Engineering, Indian Institute of Science, Bangalore 560012, KA, India.
IEEE Sens J. 2024 Feb 15;24(4):4380-4386. doi: 10.1109/JSEN.2023.3344824. Epub 2023 Dec 27.
Photoacoustic (PA) imaging provides deep tissue molecular imaging of chromophores with optical absorption contrast and ultrasonic resolution. Present PA imaging techniques are predominantly limited to one 2D plane per acquisition. 2D ultrasound transducers, required for real-time 3D PA imaging, are high-cost, complex to fabricate and have limited scalability in design. We present novel PCB-based 2D matrix ultrasound transducer arrays that are capable of being bulk manufactured at low-cost without using laborious ultrasound fabrication tools. The 2D ultrasound array specifications are easily scalable with respect to widely available PCB design and fabrication tools at low cost. To demonstrate scalability, we fabricated low (11 MHz) frequency 8x8 matrix array and high (40 MHz) frequency 4x4 matrix array by directly bonding an undiced polyvinylidene fluoride (PVDF) piezoelectric material of desired thickness to the custom designed PCB substrate. Characterization results demonstrate wideband PA receive sensitivity for both low (87%) and high (188%) frequency arrays. Volumetric PA imaging results of light absorbing targets inside optical scattering medium demonstrate improved spatial resolution and field of view with increase in aperture size.
光声（PA）成像利用光学吸收对比度和超声分辨率实现对发色团的深层组织分子成像。目前的PA成像技术每次采集主要局限于一个二维平面。实时三维PA成像所需的二维超声换能器成本高昂、制造复杂且设计上的可扩展性有限。我们展示了一种新型的基于印刷电路板（PCB）的二维矩阵超声换能器阵列，该阵列能够以低成本进行批量制造，无需使用费力的超声制造工具。二维超声阵列的规格借助广泛可用的低成本PCB设计和制造工具很容易实现扩展。为了证明可扩展性，我们通过将所需厚度的未切割聚偏二氟乙烯（PVDF）压电材料直接粘结到定制设计的PCB基板上，制造了低（11兆赫）频率的8×8矩阵阵列和高（40兆赫）频率的4×4矩阵阵列。表征结果表明，低（87%）频和高（188%）频阵列均具有宽带PA接收灵敏度。光学散射介质内光吸收目标的容积PA成像结果表明，随着孔径尺寸的增加，空间分辨率和视野得到了改善。
