Approximate back-projection method for improving lateral resolution in circular-scanning-based photoacoustic...

Area of Science:

• Medical Imaging
• Acoustic Physics
• Biomedical Engineering

Background:

• Circular-scanning photoacoustic tomography (PAT) is limited by the unaddressed effects of finite transducer apertures.
• Improving lateral resolution in PAT is crucial for detailed imaging.

Purpose of the Study:

• To develop a practical reconstruction method for circular-scanning PAT that corrects for finite transducer aperture effects.
• To enhance the lateral resolution of PAT imaging.

Main Methods:

• Proposed a novel method to calculate the spatial-temporal response (STR) of finite-sized transducers within a forward model.
• Compensated for transducer time delay and directional sensitivity using a back-projection framework.
• Evaluated the method using simulations and phantom experiments, assessing lateral resolution and mean image gradient.

Main Results:

• Simulations demonstrated equal lateral resolution for on-center and off-center targets.
• Phantom experiments showed over a two-fold improvement in lateral resolution for a point target.
• Fine structures in leaf veins were restored, and mean image gradient improved by approximately 1.3 times.

Conclusions:

• The new method effectively addresses finite transducer aperture effects in circular-scanning PAT.
• The method is robust, computationally efficient, and a viable alternative to conventional back-projection.
• This advancement is significant for the design of circular- and spherical-scanning PAT systems.