Scanning Photoacoustic Tomography of Biological Tissues with a Piezoelectricity Double-Ring Sensor

Abstract

Scanning photoacoustic tomography with a piezoelectric double-ring sensor was explored to image biological tissues, and short laser pulses irradiated tissues to generate acoustic waves by thermoelastic expansion. The laser-induced photoacoustic waves were detected by a piezoelectric double-ring sensor. This double-ring sensor has the advantage that it is more sensitive in the forward direction compared with other conventional sensors. An optical fiber for illumination of the sample was integrated with the sensor, which enabled reflection-mode detection of ultrasonic waves. Consequently, two-dimension photoacoustic tomography of biological tissues could be obtained in a manner analogous to the ultrasound B-scan mode by a linear scan over the tissue surfaces. To reach a large depth, 1064nm laser light was used in our experiments. The experimental results showed that the reconstructed photoacoustic images agree well with the structures of the samples. It demonstrated that this sensor has potential to monitoring tumor angiogenesis, and antiangiogenic therapy in vivo.

Biomedical Application of Photoacoustics: A Plethora of Opportunities

“…For PA applications, commonly used ultrasonic sensors are made of lead zirconate titanate (PZT) which is a piezoelectric crystal [25]. The basic principle of piezoelectric crystal relies on piezoelectric effect, i.e., when potential difference is applied to opposite sides of the crystal surface, mechanical displacement is observed.…”