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Ma, R.* ; Ntziachristos, V. ; Razansky, D.

Continuous acquisition scanner for whole-body multispectral optoacoustic tomography.

Vortrag: World Molecular Imaging Congress, 24th September 2009, Montreal, Canada. (2009)
By combining optical contrast with ultrasonic diffraction-limited resolution optoacoustics holds a great promise for many biological and medical imaging applications. It has been already proven capable of high-resolution visualization of vascular anatomy, tumor angiogenesis as well as other functional contrast in living tissues of small animals and humans. More recently, by applying illumination at several optical wavelengths, multispectral optoacoustic tomography (MSOT) was able to resolve distribution of smart molecular agents and fluorescent proteins with both high sensitivity and spatial resolution in optically opaque organisms and tissues. In this work, we considered the complete three-dimensional tomographic problem with size and geometry of realistic whole-body small animal imaging applications. The main difficulty arising from three-dimensional optoacoustic imaging is the long acquisition times associated with recording signals from multiple spatial projections. The acquired signals are also generally weak and the signal-to-noise ratio is low, problems that are usually solved by multiple averaging, which only further complicates matters and makes imaging challenging for most applications, especially those dealing with living subjects. Finally, when considering multispectral data acquisition, in which the same tomographic data is recorded at several different wavelengths, the imaging times become unrealistic. The scanner, presented herein, uses instead a fast continuous data acquisition approach that greatly shortens recording times over multiple projection angles. For tomographic data acquisition the samples are continuously rotated 360 degrees and the data is recorded without averaging. In this way, two dimensional image acquisition having 300 angular projections only takes about 10 seconds, while full multispectral three-dimensional image can normally take about 15 minutes to acquire with a single ultrasonic detector. We have tested various performance characteristics of the newly introduced system on tissue-mimicking phantoms containing known concentrations of fluorescent molecular agent as well as small animals. In-plane spatial resolution on the order of 50µm and vertical resolution of about 150µm were demonstrated in both phantom experiments and imaging of optically opaque organisms having typical cross-section dimensions between 1-20mm. These initial results confirmed availability of the system for high resolution whole-body visualization of molecular probes and other biomarkers.
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Publication type Other: Lecture
Corresponding Author
Conference Title World Molecular Imaging Congress
Conference Date 24th September 2009
Conference Location Montreal, Canada
Non-patent literature Publications
Institute(s) Institute of Biological and Medical Imaging (IBMI)