Fast, limited-data photoacoustic imaging for multiplexed systems using a frequency-domain estimation technique.

Area of Science:

• Biomedical Optics
• Medical Imaging
• Signal Processing

Background:

• Photoacoustic tomography (PAT) is a hybrid imaging modality combining optical absorption contrast with ultrasound spatial resolution.
• Incomplete data sets in PAT can limit imaging quality and temporal resolution, hindering the visualization of dynamic physiological processes.

Purpose of the Study:

• To develop a novel frequency-domain estimation algorithm for photoacoustic tomography.
• To simultaneously improve image quality and temporal resolution using a priori information with incomplete data.

Main Methods:

• A single-stage Wiener optimal filter is applied for data augmentation via interpolation.
• Fast Fourier Transform (FFT) methods enable real-time application with fixed or dynamic references.
• The algorithm's performance is evaluated against modified constrained backprojection using simulations and experimental data.

Main Results:

• Simulations confirm effectiveness in tracking dynamic photoacoustic activity with limited views (90 degrees) or reduced acquisition angles (< = 32).
• Experimental data show 2D tomographic imaging with temporal resolution under 130 ms for contrast uptake and washout studies.
• A 512-element curved transducer with 8:1 electronic multiplexing was utilized.

Conclusions:

• The developed algorithm achieves high spatial resolution and real-time imaging capabilities.
• It is suitable for dynamic physiological events or volumetric imaging in PAT systems.
• The method supports systems employing multiplexing or scanning techniques.