Optical and optoacoustic model-based tomography: theory and current challenges for deep tissue imaging of optical contrast

source:© 2015 IEEE Signal Processing Magazine

Light offers a range of interactions with tissue that give rise to an extensive list of methods to sense physical, chemical, or biological processes. Combined with using safe and nonionizing radiation, optical imaging is considered as a fundamental tool in the biomedical sciences.
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Fig. 1 Principles of optical and optoacoustic tomography. (a) Themorelastic expansion of an optically absorbing object (black circle) within tissue (blue circle) upon illumination by pulsed laser beams. The object expands and contracts, due to temperature variation, and releases the absorbed energy as pressure waves (dotted circles). (b) Typical time-resolved optoacoustic signal detected using an ultrasound sensor. (c) A reconstructed transversal optoacoustic image of the abdominal region of a mouse, using a two-dimensional (2-D) circular measurement system geometry,. (d) The principles of fluorescence, as electrons are excited to higher energy levels upon absorbing photons. Fluorescence photons are then emitted as the excited electrons vibrationally relax to their base states. (e) Fluorescence image acquired with a CCD camera from the dorsal side of a mouse. (f) A three-dimensional (3-D) image of a pancreatic tumor model reconstructed with concurrent X-ray CT and fluorescence molecular tomography (FMT-XCT), in 360° transillumination geometry.

P. Mohajerani, S. Tzoumas, A. Rosenthal, and V. Ntziachristos “Optical and optoacoustic model-based tomography: theory and current challenges for deep tissue imaging of optical contrast,” IEEE Signal Processing Magazine, Vol. 32, pp. 88-100 (2015).