Skull transmittance of transcranial laser in mouse models

Photobiomodulation (PBM) is a regulatory approach that utilizes red or near-infrared (NIR) light to promote tissue repair and blood microcirculation, thereby generating positive therapeutic effects at multiple levels. In recent years, as an emerging non-invasive therapy, PBM has been widely applied in the modulation of neurodegenerative diseases. However, due to the light scattering and absorption characteristics in the skull and the incomplete understanding of the intracranial propagation properties of light at different wavelengths, the application of optical techniques in transcranial modulation is greatly limited. In order to optimize the light therapeutic efficacy of neurological diseases, there is an urgent need to investigate the physical property of light transcranial spread. In this work, the transmittance of NIR light at different power levels and frequencies in the mouse skull at various points were detected. Additionally, the penetrations of light at 808 nm and 660 nm with varying tissue thickness were compared by Monte Carlo simulation analysis, providing data support for establishing the optimal therapeutic strategy of transcranial PBM.