Fluorescence can be used for instance to analyze the regulation and expression of genes, to locate proteins in cells and tissues, to follow metabolic pathways and to study the location and migration of cells. Of particular importance is the combination of fluorescence imaging with novel techniques that allow tomographic three-dimensional visualization of objects in living organisms.
At the Helmholtz Zentrum München – German Research Center for Environmental Health together with the Technische Universität München an own institute is concerned with the development and refinement of such new technologies: the Institute for Biological and Medical Imaging headed by Professor Vasilis Ntziachristos.
The quality of optical imaging in tissues is naturally limited, since beyond a penetration depth of a few hundred micrometers the photons are massively scattered due to interactions with cell membranes and organelles which results in blurred images. In the latest issue of the journal Proceedings of the National Academy of Sciences Prof. Ntziachristos and his team, together with colleagues from the Harvard Medical School and the Massachusetts General Hospital in Boston, USA, report on the use of the so-called early arriving photons together with tomographic principles. Early photons are the first photons that arrive onto a photon detector after illumination of tissue by an ultra-short photon pulse and undergo less scattering in comparison to photons arriving at later times. Compared to continuous illumination measurements a combination of these less scattered photons with 360-degree illumination-detection resulted in sharper and more accurate images of mice under investigation.
With this technique, called ‚Early Photon Tomography’ (EPT), the scientists imaged lung tumors in living mice. For this purpose they injected a substance into to the animals, which normally does not fluoresce, but becomes fluorescent after contact with certain cysteine proteases such as cathepsins. The amount of these proteases is enriched in lung tumors which allows fluorescence imaging of the tumor tissue. Comparison with conventional x-ray tomography showed, that EPT is not only a very sensitive technique for imaging of lung tumors in living organisms, but also has the potential to reveal biochemical changes that reflect the progression of the disease, which could not be detected by conventional X-ray imaging.
While early-photons are typically associated with reduced signal available for image formation, the authors demonstrated that due to the wide-field implementation, EPT operates with very small reduction in average signal strength as in conventional tomographic methods operating using continuous light illumination. In this respect EPT is a practical method for significantly improving the performance of fluorescence tomography in animals over existing implementations. At present EPT is practicable only with small animals, but – as stated by the authors of the paper – further development of the equipment can allow niche applications of the technique also with larger organisms including humans.
Michael van den Heuvel | alfa
Biocompatible 3-D tracking system has potential to improve robot-assisted surgery
17.02.2017 | Children's National Health System
Real-time MRI analysis powered by supercomputers
17.02.2017 | University of Texas at Austin, Texas Advanced Computing Center
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
20.02.2017 | Materials Sciences
20.02.2017 | Health and Medicine
20.02.2017 | Health and Medicine