New X-Ray Scanner Instantly Detects an Object's Molecular Composition

The prototype for a new X-ray scanner machine has demonstrated the ability to show not just the shape of a target but also its molecular composition - promising to revolutionize a number of fields, from medicine to geology.

A team of engineers from Duke University is behind the new X-ray scanner, with most of the concepts applied coming from an attempt to create a better bomb detection system to be used in aviation security. They present the details of their new prototype in the report "X-ray fan beam coded aperture transmission and diffraction imaging for fast material analysis," appearing in the latest Scientific Reports.

"Whether you're trying to spot a bomb in a bag or a tumor in a body, the physics is more or less the same," explains Joel Greenberg, one of the study authors and an associate research professor of electrical and computer engineering at Duke University, in a news release.He adds that from an engineering point of view, however, the applications have very different constraints. It led their team to create a smaller X-ray scanner with a higher resolution to demonstrate its potential for a variety of applications.

A Hybrid X-Ray Scanner

The technology used in the new X-ray scanner that can detect the target's molecular composition is a hybrid system combining conventional transmission radiography with diffraction tomography. The first one, X-ray transmission radiography, measures the X-rays that pass straight through the target while the latter, X-ray diffraction tomography, also takes into consideration the deflection angle and wavelength values of scattered (or reflected) X-rays from the target, creating a unique "fingerprint" corresponding to a material's molecular composition.

One of the problems in widely adopting this technology is that the scattered X-rays are very weak and very complex, with only faint signals reaching the detector. In order to create an image, it requires long periods of time as the scanner gathers data.

To work around this limitation, the Duke University researchers used a coded aperture: a layer that's like a shield with holes that allow X-rays to pass through at different angles. The trick to acquiring the unprecedented X-ray scanner results is in identifying the pattern that blocks the X-ray, which a computer reads in processing larger signals. This leads to a shorter lead time in generating images.

Creating the Prototype

In their research paper, the Duke engineering team also developed the method for fabricating high-quality and 3D-coded apertures. They also designed the machine end-to-end, including its user interface and compact footprint, resulting in a prototype built from medical imaging equipment.

Researchers noted how improved algorithms and advanced manufacturing techniques are important in achieving the intended imaging performance. They noted how security scanners are different from scanners used in an oncology lab, where scanners find cancers in the body. Specifically, security systems such as airport scanners need the ability to scan random objects quickly on the scale of centimeters. On the other hand, their target is a high-resolution scan of a smaller, well-defined target, including its molecular composition in a much shorter timeframe.

One of the tests done by the researchers was demonstrating real-time analysis of pharmaceuticals, showing that the new X-ray scanner could help manufacturers ensure that their products are reliable.

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