A unified computational and experimental approach to determine laser safety of liver tissue

Photoacoustic imaging has promising potential to be integrated into surgical guidance systems. However, this integration can potentially be limited by biosafety concerns. While laser safety guidelines exist for skin, corneal, and retinal tissue, there are no guidelines for liver tissue. We introduced the first known numerical simulation approach to determine laser safety for liver tissue and present a novel microscopy analysis framework to validate performance. Our innovative approach integrates Monte Carlo simulations of laser-tissue interaction followed by COMSOL modeling for necrosis prediction. These predictions are demonstrated with pulsed laser exposure using 30 mJ and 73 mJ laser energies with an optical wavelength of 750 nm administered for exposure durations of 1, 10, and 20 minutes. Empirical validations were performed with necrosis values quantified from immunohistochemical sections of swine liver exposed to the same laser conditions in vivo. These necrosis predictions deviated from quantitative histological results by 0.01% to 8.1%. The presented approach provides a promising alternative to traditional, time-intensive experimental methods to otherwise determine laser safety guidelines, which is expected to translate to multiple tissues and laser properties.