title: Three-dimensional photoacoustic imaging using a two-dimensional CMUT array.
abstract: 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 mum and 150 mum 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.
authors: Edward l Ginzton Laboratory, Stanford University, Stanford, CA, USA. srikantv@stanford.edu
authors: Srikant
authors: S
authors: Vaithilingam
authors: Te-Jen
authors: TJ
authors: Ma
authors: Yukio
authors: Y
authors: Furukawa
authors: Ira O
authors: IO
authors: Wygant
authors: Xuefeng
authors: X
authors: Zhuang
authors: Adam
authors: A
authors: De La Zerda
authors: Omer
authors: O
authors: Oralkan
authors: Aya
authors: A
authors: Kamaya
authors: Sanjiv S
authors: SS
authors: Gambhir
authors: R Brooke
authors: RB
authors: Jeffrey
authors: Butrus T
authors: BT
authors: Khuri-Yakub
mesh_terms: D017076:Computer-Aided Design; D054459:Elasticity Imaging Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers