News | Clinical Decision Support | December 24, 2015

New X-ray Method Uses Scattering to Visualize Nanostructures

Both in materials science and in biomedical research it is important to be able to view minute nanostructures, for example in carbon-fiber materials and bones. A team from the Technical University of Munich (TUM), the University of Lund, Charité hospital in Berlin and the Paul Scherrer Institute (PSI) have now developed a new computed tomography method based on the scattering, rather than on the absorption, of X-rays. The technique makes it possible for the first time to visualize nanostructures in objects measuring just a few millimeters, allowing the researchers to view the precise three-dimensional structure of collagen fibers in a piece of human tooth.

In principle, X-ray computed tomography (CT) has been around since the 1960s: X-ray images are taken of an object from various directions, and a computer then uses the individual images to generate a three-dimensional image of the object. Contrast is produced by the differential absorption of X-rays in dissimilar materials. However, the new method, which was developed by Franz Pfeiffer, professor for Biomedical Physics at TUM and his team utilizes the scattering of X-rays rather than their absorption. The results have now been published in the journal Nature.

Scattering Provides Detailed Images of Nanostructures

Theoretically, X-rays act like light with a very short wavelength. This principle lies at the heart of the new method: When a light is shone on a structured object, for example a CD, the reflected light produces a characteristic rainbow pattern. Although the fine grooves in the CD cannot be seen directly, the diffraction of the light rays – known as scattering – indirectly reveals the structure of the object.

The same effect can be observed with X-rays, and it is this phenomenon that the researchers take advantage of in their new technique. The advantage of X-rays over visible light is that they are able to penetrate into materials, thus providing detailed information about the internal structure of objects. The researchers have now combined this three-dimensional information from scattered X-rays with CT.

Conventional CT methods calculate exactly one value, known as a voxel, for each three-dimensional image point within an object. The new technique assigns multiple values to each voxel, as the scattered light arrives from various directions. “Thanks to this additional information, we’re able to learn a great deal more about the nanostructure of an object than with conventional CT methods. By indirectly measuring scattered X-rays, we can now visualize minute structures that are too small for direct spatial resolution,” Franz Pfeiffer explained.

Internal View of a Tooth

For demonstration purposes the scientists examined a piece of human tooth measuring around three millimeters. A large part of a human tooth is made from the substance dentin. It consists largely of mineralized collagen fibers whose structure is largely responsible for the mechanical properties of the tooth. The scientists have now visualized these tiny fiber networks.

A total of 1.4 million scatter images were taken, with the scattered light arriving from various directions. The individual images were then processed using a specially devised algorithm that builds up a complete reconstruction of the three-dimensional distribution of the scattered rays step by step. “Our algorithm calculates the precise direction of the scatter information for each image and then forms groups having the same scatter direction. This allows internal structures to be precisely reconstructed,” says Martin Bech, former postdoc at the TUM and now assistant professor at the University of Lund.

Using this method, it was possible to clearly view the three-dimensional orientation of the collagen fibers within a sample of this size for the first time. The results are in agreement with knowledge previously obtained about the structures from thin sections. “A sophisticated CT method is still more suitable for examining large objects. However, our new method makes it possible to visualize structures in the nanometer range in millimeter-sized objects at this level of precision for the first time,” said Florian Schaff, lead author of the paper.

For more information: www.nature.com/nature/journal/v527/n7578/full/nature16060.html

Related Content

Toshiba Highlights Latest CT Advancements at RSNA 2017
News | Computed Tomography (CT) | September 18, 2017
Toshiba Medical announced that it will display several new enhancements to its existing computed tomography (CT)...
Hitachi Supria True64 CT Receives FDA Clearance
Technology | Computed Tomography (CT) | September 15, 2017
September 15, 2017 — Hitachi Healthcare Americas Inc. announced it has attained U.S.
Matrix Analytics Beginning Validation of Deep Learning Lung CT Tools
News | Lung Cancer | September 13, 2017
Matrix Analytics announced it will clinically validate its LungDirect deep learning and predictive analytics tools for...
Orange County, Calif. Hospital Adopts Siemens Somatom Force CT for Cardiac Imaging
News | Computed Tomography (CT) | September 12, 2017
Hoag Memorial Hospital Presbyterian recently became the first hospital in Orange County, Calif., to install the Siemens...
Patient X-ray radiation exposure from medical imaging has been a hot topic in radiology and has prompted the implementation of radiation dose monitoring systems.
Feature | Radiation Dose Management | September 08, 2017 | By Dave Fornell
Patient X-ray radiation exposure from medical imaging has been a hot topic in radiology and has prompted the...
Technology | Radiation Dose Management | September 07, 2017
September 7, 2017 — Sapheneia and Scannerside received U.S.
20/20 GeneSystems Launches AI-Based Lung Cancer Detection Technology in China
Technology | Lung Cancer | August 28, 2017
20/20 GeneSystems Inc. recently released in China what is believed to be the world’s first machine learning algorithm...
Philips to Develop FFR-CT in Partnership With HeartFlow
News | CT Angiography (CTA) | August 28, 2017
August 28, 2017 — Philips Healthcare and HeartFlow Inc.
St. Cloud Hospital Installs Toshiba Aquilion One Genesis CT for Emergency Department
News | Computed Tomography (CT) | August 23, 2017
Central Minnesota residents now have access to advanced computed tomography (CT) technology that is safe and fast at St...
Overlay Init