Performance evaluation of image reconstruction algorithms for photoacoustic tomography

Photoacoustic (PA) imaging uses the acoustic energy produced by some materials when heated with a laser due to the photoacoustic effect. Photoacoustic tomography (PAT) can be a powerful tool in medical imaging, since it combines the optical contrast with the high penetration of ultrasound to generate anatomical, molecular and functional images. To create the images, beamforming algorithms are used as commonly in ultrasonic imaging. The most used algorithm is Delay-and-Sum (DAS) beamforming because is computationally efficient and very easy to implement, however, it has some limitations as it offers low image resolution and contrast. To overcome these image quality problems, improvements have emerged over the typical DAS to obtain better image quality and narrower main lobes. They are based on combining the signals of the different elements, windowing the signal, or even calculating the optimal apodization for each pixel based on the signals received by the ultrasonic elements. This work is a numerical and experimental study that uses the spatial resolution and the signal to noise ratio to evaluate the performance of the main reconstruction algorithms used in PAT.