Broadband All-Optical Plane-Wave Ultrasound Imaging System Based on a Fabry-Perot Scanner.

Area of Science:

• Biomedical Optics
• Acoustic Imaging
• Materials Science

Background:

• Conventional ultrasound imaging faces limitations in resolution and image quality for superficial tissues.
• Photoacoustic imaging offers complementary information but often requires separate systems.
• All-optical methods present an opportunity to overcome limitations of traditional ultrasound transducers.

Purpose of the Study:

• To develop and characterize a broadband all-optical plane-wave ultrasound imaging system.
• To achieve high-resolution 3-D imaging of biological tissues using a novel integrated approach.
• To evaluate the system's performance for superficial tissue imaging and potential for dual-mode imaging.

Main Methods:

• Utilized a planar Fabry-Perot (FP) scanner for ultrasound detection.
• Employed a carbon-nanotube-polydimethylsiloxane (CNT-PDMS) composite film for photoacoustic ultrasound generation.
• Implemented k-space reconstruction algorithm for 3-D image recovery.
• Measured instrument line-spread function (LSF) for spatial resolution assessment.

Main Results:

• Generated monopolar plane-wave ultrasound pulses with MPa-range peak pressures and 22 MHz -6-dB bandwidth.
• Achieved a sensor -3-dB bandwidth of 30 MHz.
• Demonstrated lateral LSF ranging from 46 to 65 µm and vertical LSF of 10 µm.
• Successfully imaged phantoms and ex vivo tissue samples, showing high-resolution 3-D scatterer distribution.

Conclusions:

• The all-optical system provides high-resolution 3-D ultrasound imaging capabilities.
• The integrated CNT-PDMS/FP system offers potential for improved image quality and resolution over conventional piezoelectric scanners for superficial tissues.
• The system could be developed for dual-mode all-optical ultrasound and photoacoustic imaging.