Weighted Non-linear Beamformer for PLD-based Photoacoustic Imaging Systems: Initial Results

This paper introduces a new nonlinear beamforming method, Filtered Delayed Euclidean-weighted Multiply and Sum (F-DewMAS) beamformer, for photoacoustic imaging, especially useful for pulsed laser diode (PLD)-based systems. F-DewMAS technique enhances image quality by addressing the limitations of conventional Delay and Sum (DAS) and Filtered Delay Multiply and Sum (F-DMAS) beamformers. The different beamformers DAS, F-DMAS, and F-DewMAS were compared in terms of Axial Resolution (AR) Lateral Resolution (LR), Contrast Ratio (CR), Contrast to Noise Ratio (CNR), and Signal to Noise Ratio (SNR). The study involves simulation and phantom experiment to evaluate F-DewMAS beamformer. Simulation using 41 point sources arranged in the shape of "IITM" demonstrated that F-DewMAS outperforms both DAS and F-DMAS. Phantom experiment with nine 0.5 mm diameter graphite lead absorbers show that F-DewMAS achieves up to a 24% improvement in CR, 28% in CNR, and 31% in SNR compared to DAS. Analysis of Full Width Half Maximum (FWHM) measurements shows noticeable improvements in both axial and lateral resolution. F-DewMAS achieves an average axial resolution of 0.356 mm, showing a 33% improvement over DAS (0.532 mm) and surpassing F-DMAS (0.458 mm). For lateral resolution, F-DewMAS averages 1.194 mm, demonstrating a 38% improvement over DAS (1.916 mm) and exceeding F-DMAS (1.424 mm). These findings suggest that F-DewMAS is a promising approach for improving photoacoustic image quality and could serve as a practical alternative to traditional beamforming techniques.Clinical RelevanceThe proposed technique improves the contrast and resolution in PLD-based photoacoustic imaging, not only enabling more precise diagnostics but also aiding in the integration of point of care photoacoustic imaging into clinical practice.