Material Detail

This video was recorded at Kolokviji na Institutu "Jožef Stefan". Optoacoustics provides high optical contrast without the handicap of poor resolution in imaging of optically turbid tissues. In biomedical optoacoustics, tissue is illuminated with short laser pulses. The light is scattered inside the tissue and heats absorbing structures, such as blood vessels, hidden deeply inside the tissue. Image contrast is therefore provided by light absorbing chromophores, either endogenous (such as oxy- or deoxyhemoglobin) or exogenous (e.g. dyes, nanoparticles or quantum dots). By means of the thermoelastic effect, the inhomogeneous heating generates pressure transients exactly representing the absorbing structures. These acoustic transients propagate to the tissue surface and can be detected with an appropriate ultrasound transducer. In one-dimensional optoacoustic measurements, time delay between the laser pulse and detected pressure transient, its amplitude and temporal profile provide information about the location, strength and spatial dimension of the acoustic source. Three-dimensional images can be reconstructed by scanning the transducer. The image quality depends on a number of factors, including the irradiation geometry and image reconstruction algorithm. The talk will give an overview of the possibilities and limitations of optoacoustic imaging in turbid tissues, especially in terms of image contrast and depth resolution.

Disciplines:

• Health Sciences

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