Multispectral optoacoustic tomography-volumetric color hearing in real time

Biomedical optoacoustics has emerged in the recent decade as a powerful tool for high-resolution visualization of optical contrast, overcoming a variety of longstanding limitations imposed by light scattering in deep tissues. But true performance of optoacoustic imaging techniques can only be exploited when excitation at multiple wavelengths is used in order to enable highly sensitive spectral differentiation of intrinsic biomarkers and extrinsically administered contrast agents. By detecting tiny sound vibrations, resulting from selective absorption of light at multiple wavelengths, multispectral optoacoustic tomography (MSOT) can now "hear color" in three dimensions, i.e., deliver volumetric spectrally enriched (color) images from deep living tissues at high spatial resolution and in real time. These new-found imaging abilities directly relate to preclinical screening applications in animal models and are foreseen to significantly impact clinical decision making as well. This paper provides the technical essentials of MSOT, including latest developments in the inverse theory, spectral processing algorithms, and imaging instrumentation. Furthermore, a separate section is devoted to the state of the art of molecular imaging applications using MSOT.