Optimization of light illumination for photoacoustic computed tomography of human infant brain

Photoacoustic imaging (PAI) is an imaging modality for obtaining absorption coefficient at every location inside the tissue based on the detected photoacoustic signals. PA image reconstruction aims to determine the initial PA pressure everywhere inside the tissue. The pressure is proportional to both absorption coefficient and light fluence. Provided that fluence is homogenous, the reconstructed image will be an accurate mapping of the absorption coefficient of the tissue. Here we presented a method for obtaining uniform fluence inside the region of interest. We created a large dataset of fluence maps for different source locations, diameters and numerical apertures with Monte Carlo simulations, then used this dataset to solve an optimization problem for finding the source configuration which results in the best fluence distribution.