PhocoSpace: An open-source simulation package to implement photoacoustic spatial coherence theory

We previously developed a novel photoacoustic spatial coherence theory and demonstrated its ability to model and optimize a wide range of photoacoustic short-lag spatial coherence (SLSC) imaging parameters, target geometries, and light profile sizes. Recognizing the broad potential of this theoretical application, we developed PhocoSpace, an open-source toolbox to simulate the coherence of photoacoustic signals correlated in the transducer space dimension. PhocoSpace is provided as a MATLAB extension, and this paper serves as an introductory user manual containing tutorials to illustrate toolbox capabilities. Target geometries, fluence distributions within an imaging plane, and parameters describing acoustic receivers (e.g., transducer element pitch, bandwidth, aperture size) may each be customized to model experimental setups, clinical scenarios, and imaging equipment specifications. We demonstrate that PhocoSpace is a flexible in silico tool to predict photoacoustic spatial coherence functions, determine expected photoacoustic SLSC image quality, and characterize multiple possible coherence-based photoacoustic image optimizations without requiring lengthy experimental data acquisition. In addition, this software package establishes a foundation for future investigations into alternative photoacoustic spatial coherence-based signal processing methods.