In vivo imaging research
VisEn has pioneered fluorescence-based Quantitative Tomography for in vivo imaging research. Imaging systems based on VisEn's proprietary FMT technology provide non-invasive, whole body, deep tissue imaging in small animal models and generate 3D, information-rich results. These systems are used for research in oncology as well as inflammatory, pulmonary, cardiovascular and skeletal disease. Biological targets and pathways can be monitored and quantified in real time - giving a deeper understanding of the biology underlying disease mechanisms and therapeutic response.
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Sagittal, transverse and coronal reconstructions of a mouse prostate scanned in vivo using AngioSense. Courtesy of Drs. H. Alencar and U. Mahmood, Massachusetts General Hospital.
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Absolute quantification based on robust data even within deep tissue
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Quantitative imaging data |
Accurate quantification in deep tissue. True tomographic reconstruction avoids the risk of obtaining misleading data. Regardless of signal depth, imaging systems based on FMT technology extract more information from the fluorescence signal than conventional planar or single-view instruments.
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Readouts from conventional optical imagers show erroneously decreasing signals, due to depth effects. FMT technology provides uniformly accurate measurement regardless of depth.
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ROI Analysis yields 0.97nmol estimate from tomographic reconstruction after direct injection of 1 nmol AngioSense.
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Linearity of measurement. True tomographic reconstruction avoids errors in data interpretation. The result is a quantifiable measurement of fluorochrome concentration at any depth, exhibiting strict linearity in vivo over a broad range of biologically-relevant fluorescence agent concentrations.
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Channel 1: Reconstructed vs. Actual Concentration
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Channel 2: Reconstructed vs. Actual Concentration
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Resin phantoms with AngioSense 680 and AngioSense 750 at 2.5 mm depth from front surface. Phantoms were made of an optically clear polyester resin cast in 60mm x 60mm x 15mm blocks with a dispersion of TiO2 and ink to match absorption and scattering properties of mouse tissue.
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Strict linearity over a broad range of biologically relevant fluorochrome concentrations
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Limitations in conventional optical imaging |
Photon scattering and in vivo linearity
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One of the key limitations of optical imaging is the natural scattering of photons by biological tissue. As a result of this scattering, there is no linearity between raw camera counts captured at the surface of an imaging subject and the true signal intensity emanating from within the subject, regardless of system calibration.
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Photon scattering in tissue
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Measuring fluorescence at depth: ambiguity between estimates of depth, size and concentration distorts and limits quantitative accuracy
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Consequently, the depth, size and associated absolute fluorescence of a fluorescent signal cannot be accurately determined by camera count readouts from conventional imaging systems.
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More details on
in vivo imaging based on FMT technology
