Volumetric and Simultaneous Photoacoustic and Ultrasound Imaging With a Conventional Linear Array in a Multiview...

Area of Science:

• Biomedical Imaging
• Medical Physics
• Optical Engineering

Background:

• Multimodal imaging offers complementary diagnostic information.
• Combining 3-D photoacoustic (PA) and ultrasound (US) imaging presents challenges in maintaining image quality for both modalities.
• Existing methods often involve technical compromises, leading to suboptimal PA or US image quality.

Purpose of the Study:

• To develop a translatable, high-quality, simultaneously coregistered dual-mode PA/US 3-D tomography system.
• To overcome limitations of current PA/US imaging techniques.
• To enable precise monitoring of biological processes and nanoagent accumulation.

Main Methods:

• Implemented volumetric imaging using a synthetic aperture approach with interlaced PA and US acquisitions.
• Employed a rotate-translate scan with a 5-MHz linear array (12 angles, 30-mm translation) for a 21-mm diameter cylindrical volume.
• Developed an original calibration method using a thread phantom to estimate geometrical and temporal parameters for coregistration via global optimization.

Main Results:

• Achieved accurate estimation of seven calibration parameters (six geometrical, one temporal) with high accuracy.
• Validated calibration repeatability through experimental estimations.
• Demonstrated superposition distance within 10% of the acoustic wavelength and uniform spatial resolution of wavelength order.

Conclusions:

• The developed dual-mode PA/US tomography provides high-quality, simultaneously coregistered volumetric imaging.
• This technique offers potential for more sensitive and robust detection and follow-up of biological changes.
• It is suitable for monitoring slower-kinetic phenomena, such as nanoagent accumulation in living systems.