Three-dimensional photoacoustic imaging using a two-dimensional CMUT array

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2009-11, Vol.56 (11), p.2411-2419
• Main Authors: Vaithilingam, S., Ma, T-J., Furukawa, Y., Wygant, I.O., Zhuang, X., De La Zerda, A., Oralkan, Omer, Kamaya, Aya, Gambhir, Sanjiv s., Jeffrey, R. Brooke, Khuri-yakub, Butrus T.
• Format: Article
• Language: English
• Subjects: Acoustic arrays; Acoustic imaging; Acoustic pulses; Acoustic signal processing; Acoustics; Arrays; Biological and medical sciences; Computer simulation; Computer-Aided Design; Elasticity Imaging Techniques - instrumentation; Equipment Design; Equipment Failure Analysis; Exact sciences and technology; Feasibility Studies; Fundamental areas of phenomenology (including applications); Imaging; Imaging phantoms; Imaging, Three-Dimensional - instrumentation; Investigative techniques, diagnostic techniques (general aspects); Lasers; Medical sciences; Miscellaneous. Technology; Nanostructure; Optical imaging; Optical pulse generation; Physics; Reproducibility of Results; Sensitivity and Specificity; Transducers; Transduction; acoustical devices for the generation and reproduction of sound; Tunable circuits and devices; Two dimensional; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonic transducer arrays; Ultrasonic transducers
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFc.2009.1329

In this paper, we describe using a 2-D array of capacitive micromachined ultrasonic transducers (CMUTs) to perform 3-D photoacoustic and acoustic imaging. A tunable optical parametric oscillator laser system that generates nanosecond laser pulses was used to induce the photoacoustic signals. To demonstrate the feasibility of the system, 2 different phantoms were imaged. The first phantom consisted of alternating black and transparent fishing lines of 180 μm and 150 μm diameter, respectively. The second phantom comprised polyethylene tubes, embedded in chicken breast tissue, filled with liquids such as the dye indocyanine green, pig blood, and a mixture of the 2. The tubes were embedded at a depth of 0.8 cm inside the tissue and were at an overall distance of 1.8 cm from the CMUT array. Two-dimensional cross-sectional slices and 3-D volume rendered images of pulse-echo data as well as photoacoustic data are presented. The profile and beamwidths of the fishing line are analyzed and compared with a numerical simulation carried out using the Field II ultrasound simulation software. We investigated using a large aperture (64 x 64 element array) to perform photoacoustic and acoustic imaging by mechanically scanning a smaller CMUT array (16 x 16 elements). Two-dimensional transducer arrays overcome many of the limitations of a mechanically scanned system and enable volumetric imaging. Advantages of CMUT technology for photoacoustic imaging include the ease of integration with electronics, ability to fabricate large, fully populated 2-D arrays with arbitrary geometries, wide-bandwidth arrays and high-frequency arrays. A CMUT based photoacoustic system is proposed as a viable alternative to a piezoelectric transducer based photoacoustic systems.