Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


High-contrast, high-resolution CT scans now possible at reduced dose

Soft body tissue can now be imaged with incredible detail using X-rays thanks to a new low dose CT-scan technique

Jointly released by ESRF - TU München and Synchrotron SOLEIL

This shows 3D renderings of rat testicle (different cuts through the same tomogram). Detail within the image shows the epididymis (blue), adipose tissue (yellowish) and the testis itself. Inside the testis, clearly visible are the seminiferous tubules (with concentric structure) and the vessels (in dark red) especially visible at the edges of the organ. Image data collected at ESRF beamline ID19
Credit: ESRF/I. Zanette

Scientists have developed an X-ray imaging method that could drastically improve the contrast of computed tomography (CT) scans whilst reducing the radiation dose deposited during the scan. The new method is based on the combination of the high contrast obtained by an X-ray technique known as grating interferometry with the three-dimensional capabilities of CT. It is also compatible with clinical CT apparatus, where an X-ray source and detector rotate continuously around the patient during the scan. The results are published in Proceedings of the National Academy of Sciences (PNAS) dated 4-8 June 2012.

The main author of the paper is Irene Zanette from the European Synchrotron Radiation Facility ESRF (Grenoble, FR) and Technical University of Munich TUM (DE), and the team also comprises scientists from the Paul Scherrer Institute PSI (Villigen, CH), the Karlsruhe Institute of Technology KIT (DE), and Synchrotron SOLEIL (Gif-sur-Yvette, FR).

The conventional way of producing X-ray images is to shine an X-ray beam on the investigated object and measure the transmitted intensity behind it. This is the method that W.C. Röntgen developed in 1895, just after he discovered X-rays. To the present day, it is commonly used, for example, in hospitals and for security screening at airports. However, since this technique relies on variations in how the different constituents of an object absorb X-rays, it also has severe limitations notably in medical X-raying where cancerous and healthy soft tissue often do not show enough contrast to be clearly distinguished.

In the past years, a lot of effort has therefore been put into the development of new X-ray imaging techniques that do not rely solely on absorption but increase the contrast through the observation of other types of interaction between X-rays and matter.

Of these new methods, a very promising one is the so-called "X-ray grating interferometry", in which microstructures, gratings developed at PSI and KIT, serve as optical elements for X-rays. The setup for this contrast-enhancing technique is simple and compact, and it can be combined with computed tomography (CT) X-ray scanners to yield virtual slice images and full 3D information of an object. Over the past decade, grating interferometry has been constantly improved, with a focus on medical applications.

The team of scientists has now made an important step towards clinical implementation of this technique – a new measurement protocol called "sliding window" technique. "We wanted to shorten the gap between the potential offered by this extremely powerful technique and its application in the biomedical field. Our sliding window method reduces the dose and acquisition time and makes grating interferometry compatible with the continuous rotation of the gantry used in clinical CT", says Timm Weitkamp from Synchrotron SOLEIL.

Grating interferometry uses, in addition to information on absorption, measurements of X-ray phase changes to produce "differential phase contrast" images. Density differences of only 0.5 mg/cm3 can be discerned using grating-based phase contrast.

To demonstrate the exceptional resolution of the new technique, various soft tissue body parts of a small mammalian specimen, a rat, were imaged. Within the tests, rendered in 3D, minute details are visible such as the individual seminiferous tubules, tiny tubes in which sperm cells are formed. "These structures are simply invisible in standard CT, even in high-resolution setups – not only because of their tiny size, but even more so because they hardly give any contrast", explains Zanette, who was recently presented the ESRF Young Scientist Award for her work.

In addition to phase contrast, grating interferometry can also yield so-called "dark-field" tomography images. These show the presence of sub-pixel-size structures in the object, such as fibres, cracks or nanosized pores. In the study now reported in PNAS, wings of a wasp fossilised in amber – mostly invisible in previous X-ray investigations of the same specimen – were revealed in their full length with the dark-field signal. These results encourage the use of dark-field imaging not only in palaeontology and materials science, but also in the medical field, for example to reveal minuscule cracks in bones or small fibres in soft tissue.

The complementarity of the image signals accessed with grating interferometry and the new simple and fast acquisition procedure make grating interferometry an attractive technique for high-sensitivity imaging in the biomedical field, in materials science and in palaeontology, and possibly also in future hospital CT scanners.

Claus Habfast | EurekAlert!
Further information:

More articles from Medical Engineering:

nachricht Gentle sensors for diagnosing brain disorders
29.09.2016 | King Abdullah University of Science and Technology

nachricht New imaging technique in Alzheimer’s disease - opens up possibilities for new drug development
28.09.2016 | Lund University

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>