Photoacoustic imaging of rat kidney tissue oxygenation using second near-infrared wavelengths

sPAI using NIR-II wavelengths improved the accuracy of tissue sO 2 measurements. This is likely due to reduced scattering, which reduces the attenuation and, therefore, the impact of spectral coloring in this wavelength range. Combined with the increased safe skin exposure fluence limits in this wavelength range, these results demonstrate the potential to use NIR-II wavelengths for quantitative sPAI of sO 2 from deep heterogeneous tissues.