Optimizing light delivery for photoacoustic imaging using Monte Carlo simulations
Photoacoustic imaging functions via two foundations: light delivery and acoustic signal reception. In order for acoustic signal to be received and processed into an image, photons must first penetrate the tissue. However, biological media highly attenuates light, and the maximum imaging depth for photoacoustic images lies between 2-3 centimeters. Thus, models and simulations are integral to approach this problem, and they can be used to easily change imaging parameters and simulate various conditions. This study used a MATLAB Monte Carlo simulation algorithm to model and simulate a homogeneous placental tissue sample. The simulated data was compared to experimental ex vivo placental images taken under identical conditions of the simulation. These two data sets were used to gauge the simulation’s accuracy to predicting fluence trends in tissue, and the results were then applied to a heterogeneous tissue model simulating in vivo placental imaging. It was found that to maximize fluence in the placenta during in vivo imaging, 808 nm and 950 nm both offer different benefits to maximize fluence in the placenta. This simulation toolbox can be used to determine which experimental setup can maximize fluence in photoacoustic images, resulting in high-quality, high-contrast images.