Researchers are developing a new approach for visualization of oxygen in the tissues -
Learn to look inside a body without cutting open is always an important part of medical research. One of the great challenges of imaging remains the visualization of oxygen in the tissues. A team led by Professor Vasilis Ntziachristos, chair for biological imaging at the Technische Universität München (TUM) and director of the Institute for Biological and Medical Imaging at the Helmholtz Zentrum München, has developed a new approach to this task.
The imaging of tissue oxygenation is not simple; various techniques have been proposed, but each has its shortcomings. In recent years, research in this area has focused on optoacoustic methods. These, optoacoustic tomography especially multispectral (MSOT) form one of the key areas of research Vasilis Ntziachristos
In simple terms, MSOT transforms light into sound and then into information visual. First, a weak pulsed laser beam is directed at the tissue. absorbent molecules and cells react with a minute vibration, which in turn, creates sound signals. The sound signals are then picked up by acoustic sensors and translated into images. How molecules and cells react to the laser beam provides an overview of their perspective and thus in their biochemical properties.
complex tissue is a barrier to optoacoustic imaging
Although MSOT can, in theory, be used to indicate the amount of oxygen can be found in the blood, there is a major obstacle: the light intensity changes with depth, not only because the light was filtered through all the layers of fabric he went through, but also because the tissue structures different may have different properties that affect how the light is scattered and absorbed. In the past, there have been several attempts to solve this problem by calculating how the fabric will affect the propagation of light. "However, due to the high optical complexity of tissue, this approach until now could not be applied flexibly in optoacoustic images of living subjects tissues," said Stratis Tzoumas, first author of a study published in Nature Communications , in which scientists describe their new method.
a new description of light distribution in tissues
Ntziachristos, Tzoumas, and colleagues came up with a completely different approach instead of describing the spatial distribution of light, their imaging method eMSOT -. e means "eigenspectra" - avoids simulating the path of light through a total complex tissue. instead, the new method is based on the discovery that the spectrum of the light propagating in the tissue can be described using a small number of basis spectra. eMSOT uses data from a vector MSOT-device combined with a new algorithm which is based on this new way of describing the spectrum of light to correct the effects of the propagation of light in the tissue and obtain precise images of blood oxygenation in the tissue.
With eMSOT, scientists were able to visualize the level of oxygenation of the blood of the living tissue up to one centimeter below the skin surface. "Theoretically, the imaging depth can be extended to more than that," said Stratis Tzoumas. "There is, however, a limit to about three because at some point, the light can not penetrate the tissue further. "scientists have observed greatly improved accuracy in eMSOT compared to optical approaches and optoacoustic earlier. in addition to being non-invasive and without radiation, eMSOT also provides comparable or higher resolution both spatially and temporally, that . other optical imaging methods "information on the amount of oxygen in the tissues is important regarding the different areas of research and treatment - for tumor growth for example or in the measures metabolism, "says Vasilis Ntziachristos." It may be that eMSOT becomes the method of the gold standard, once it is ready for clinical use. "
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