Multiview spatial compounding using lens-based photoacoustic imaging system.

Area of Science:

• Medical Imaging
• Acoustic Lens Technology
• Biomedical Optics

Background:

• Acoustic lenses offer a computationally efficient alternative to traditional reconstruction algorithms in photoacoustic (PA) imaging, enabling real-time and cost-effective systems.
• However, fixed focal lengths lead to spatially varying and asymmetric Point Spread Functions (PSFs), limiting resolution, particularly lateral resolution.

Purpose of the Study:

• To improve the Point Spread Function (PSF) characteristics in photoacoustic imaging systems utilizing acoustic lenses.
• To enhance image resolution and Signal to Noise Ratio (SNR) by addressing spatial variations and asymmetry in the PSF.

Main Methods:

• Spatial compounding of multiple views acquired at varying angles to mitigate PSF asymmetry and spatial variation.
• Development and evaluation of a residual refocusing algorithm for cases where multiple views are not feasible.
• Simulation-based evaluation of PSF improvement and experimental validation on phantoms and ex vivo tissues.

Main Results:

• Spatial compounding demonstrated significant improvements in PSF characteristics, resolution, and SNR.
• Experimental results on phantoms and ex vivo tissues confirmed overall image quality enhancement.
• The residual refocusing algorithm provided a viable alternative for improving image quality when multi-view acquisition is not possible.

Conclusions:

• Spatial compounding is an effective technique for enhancing photoacoustic imaging quality with acoustic lenses, particularly for applications like thyroid, breast, and small animal imaging.
• Residual refocusing serves as a valuable alternative or complementary method when multi-view imaging is constrained.
• The study highlights practical implications for developing advanced, high-quality photoacoustic imaging systems.