Curved array photoacoustic tomographic system for small animal imaging

Area of Science:

• Biomedical Imaging
• Optical Imaging
• Acoustic Imaging

Background:

• Photoacoustic imaging offers high resolution and contrast for biological tissues.
• Existing systems often face limitations in speed, resolution, or penetration depth for small animal studies.

Purpose of the Study:

• To systematically characterize a novel photoacoustic imaging system optimized for rapid, high-resolution tomographic imaging of small animals.
• To evaluate the system's performance in terms of resolution, sensitivity, and imaging depth.

Main Methods:

• Utilized a 128-element ultrasonic transducer array (5 MHz, 80% bandwidth) in a quarter-circle configuration.
• Employed a 16-channel data-acquisition module for rapid image capture (<1 s for 90-deg FOV).
• Performed tomographic imaging using sample rotation for a full 360-deg scan (<15 s).

Main Results:

• Achieved better than 200-micrometer resolution on phantom targets.
• Demonstrated high-sensitivity detection of 580-micrometer blood vessels at depths >3 cm in a turbid medium (μs'=7.8 cm⁻¹).
• Successfully imaged ex vivo mouse brain vasculature, resolving sub-200-micrometer vessels through >2 cm of turbid tissue using intrinsic contrast.

Conclusions:

• The developed photoacoustic imaging system provides rapid, high-resolution, and deep-tissue imaging capabilities for small animals.
• This system enables novel investigations into biological structures and disease processes with unprecedented detail.
• The demonstration of sub-200-micrometer vessel resolution in deep, turbid tissues using intrinsic contrast is a significant advancement in the field.