3-D X-ray films show internal movement dynamics

Mar 13, 2014
The 3D radiograph shows the hip joints of the weevil, but only the 3D X-ray film shows how they interlock during climbing. Credit: dos Santos Rolo et al., PNAS, 2014

How does the hip joint of a crawling weevil move? A technique to record 3D X-ray films showing the internal movement dynamics in a spatially precise manner and, at the same time, in the temporal dimension has now been developed by researchers at ANKA, KIT's Synchrotron Radiation Source. The scientists applied this technique to a living weevil. From up to 100,000 two-dimensional radiographs per second, they generated complete 3D film sequences in real time or slow motion. The results are now published in the Proceedings of the National Academy of Sciences (PNAS).

Three-dimensional represent internal structures, but do not provide any information about movement sequences. Conventional computer tomography is not efficient enough to reproduce movement in a spatially precise manner and, at the same time, in the temporal dimension. Every individual three-dimensional image, called tomogram, is reconstructed from hundreds of two-dimensional radiographs. "To produce highly resolved tomograms at such recording speed, we had to adjust every setting screw, from the X-ray source to the pixel detector and we optimally attuned all process steps to each other," Tomy dos Santos Rolo says. The doctoral student is the leading developer of the experimental setup. By making the 3D image frequencies approach the image rates known for 2D cine films, he reached the world record in high-speed tomography, i.e. a real 3D film with microscopic magnification.

For scientific evaluation, the three-dimensional contours of anatomic structures have to be clearly visible. This is achieved by the so-called phase contrast. If highly parallel X-rays pass the biological examination object, wave optics phenomena occur, which highlight the inner and outer contours.

In the weevil’s hip joint, large skeleton parts move relative to each other and interlock like a screw and a nut. Credit: dos Santos Rolo et al., PNAS, 2014

"It is these contours that matter to us. We want to distinguish individual functional elements that move relative to each other. That is why we need sharp contours," Alexey Ershov, the expert for image analysis in the team, says. From the X-ray source to movement analysis, all process stages are designed to filter out image noise without reducing contrast. This also applies to the mathematic algorithms optimized for radiography. They reconstruct three spatial and one temporal dimension and derive exact movement patterns from the data.

In line with the first moving images – cinematography –, the scientists call their method "cinetomography". In the late 19th century, movements of big animals were studied. Today, researchers can analyze internal biological processes of small organisms, as is now demonstrated for the recently discovered screw joint of the weevil. Insects, spiders, and crustaceans make up more than 80% of all species.

Cinetomography cannot only be used to image in four dimensions biological and biotechnological processes, but also combustion processes relevant to industry.

Explore further: New insights found in black hole collisions

More information: Tomy dos Santos Rolo, Alexey Ershov, Thomas van de Kamp, and Tilo Baumbach: "In vivo X-ray cine-tomography for tracking morphological dynamics," PNAS Early Edition (2014), DOI: 10.1073/pnas.1308650111

Related Stories

X-ray tomography on a living frog embryo

May 16, 2013

Classical X-ray radiographs provide information about internal, absorptive structures of organisms such as bones. Alternatively, X-rays can also image soft tissues throughout early embryonic development of ...

Conservative, high-precision computed tomography

Feb 06, 2014

A new CT scanner from Siemens reduces the radiation dosage for patients by as much as a half, depending on the examination. The machine operates with unprecedented speed and can record image sequences with ...

Cancer cells don't take 'drunken' walks through the body

Mar 11, 2014

Because of results seen in flat lab dishes, biologists have believed that cancers cells move through the body in a slow, aimless fashion, resembling an intoxicated person who cannot walk three steps in a straight line. This ...

Recommended for you

New insights found in black hole collisions

Mar 27, 2015

New research provides revelations about the most energetic event in the universe—the merging of two spinning, orbiting black holes into a much larger black hole.

X-rays probe LHC for cause of short circuit

Mar 27, 2015

The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, ...

Swimming algae offer insights into living fluid dynamics

Mar 27, 2015

None of us would be alive if sperm cells didn't know how to swim, or if the cilia in our lungs couldn't prevent fluid buildup. But we know very little about the dynamics of so-called "living fluids," those ...

Fluctuation X-ray scattering

Mar 26, 2015

In biology, materials science and the energy sciences, structural information provides important insights into the understanding of matter. The link between a structure and its properties can suggest new ...

Hydrodynamics approaches to granular matter

Mar 26, 2015

Sand, rocks, grains, salt or sugar are what physicists call granular media. A better understanding of granular media is important - particularly when mixed with water and air, as it forms the foundations of houses and off-shore ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.