Video-rate all-optical ultrasound imaging

Area of Science:

• Biomedical Optics
• Medical Imaging
• Acoustic Engineering

Background:

• All-optical ultrasound imaging offers advantages like electromagnetic interference immunity and wide bandwidths.
• Previous all-optical ultrasound systems faced limitations due to long acquisition times, hindering clinical use.
• High-quality 2D and 3D imaging have been achieved, but real-time capabilities were lacking.

Purpose of the Study:

• To develop the first all-optical ultrasound imaging system capable of real-time, video-rate 2D imaging of biological tissue.
• To overcome the slow acquisition times that have previously limited clinical applications of all-optical ultrasound.

Main Methods:

• Utilized a spatially extended nano-composite optical ultrasound generator for enhanced acoustic generation.
• Employed a highly sensitive fibre-optic acoustic receiver for improved signal detection.
• Implemented eccentric illumination and a fast galvo mirror to dynamically synthesize source arrays for optimized directivity and scanning.

Main Results:

• Achieved a sustained frame rate of 15 Hz, enabling video-rate imaging.
• Demonstrated a dynamic range of 30 dB and a penetration depth of at least 6 mm.
• Obtained a resolution of 75 µm (axial) by 100 µm (lateral) and captured dynamics of a pulsating ex vivo carotid artery.

Conclusions:

• The developed system represents a significant advancement in all-optical ultrasound imaging, enabling real-time 2D visualization of biological tissues.
• This technology overcomes previous acquisition time limitations, paving the way for potential clinical applications.
• The system's performance metrics (frame rate, resolution, depth) demonstrate its viability for dynamic tissue imaging.