Introduction:
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Since the introduction of the X-ray computed tomography in the 60's, it became one of the most important methods of non-invasive biomedical imaging. Quite a few other modalities have been introduced since then, and become indispensable tools in medicine, biology, and other areas of science and engineering. These modalities differ by types of waves or particles used to scan the object of interest, which, in turn, determines which biological (or physical) features they can or cannot detect. In all of these techniques images are not formed directly, but are being reconstructed by solving inverse problems with respect to the coefficients of the partial differential equations describing propagation of the corresponding type of waves through the medium. These problems are frequently strongly unstable, thus disallowing reconstructions of high-quality images. In many cases, modalities that are capable of delivering high-resolution images (such as utrasound) cannot distinguish between healthy and cancerous tissues, and sensitive modalities (such as electrical impedance tomography) require solving an extremely unstable inverse problem.
Recently, several novel "hybrid" or "multi-physics" modalities have been introduced and become an object of intensive research. Among these methods are thermo- and photo-acoustic tomography, acousto- electric tomography, ultrasound-modulated optical tomography, and others. These technique utilize physical coupling between two different types of waves (for example, infra-red radiation and ultrasound) in order to overcome the low sensitivity or high instability associated with particular types of radiation, thus, yielding information that cannot be obtained by traditional methods.
The theoretical and algorithmic foundations of these multi-physics modalities are being actively developed. This session brings together leading experts on thermo- and photoacoustic tomography, acoustically modulated optical and electric impedance tomography, MRI assisted elastography and current density tomography, and other related techniques. |
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