A new x-ray technique for detecting explosives could also identify tumors

A new x-ray technique for detecting explosives could also identify tumors

While the obvious application would be to scan airports for bombs and other dangerous substances, the findings described in Nature Communications today could also be used to detect cracks in buildings and rust in buildings and could eventually be used to diagnose early-stage cancers.

A team of researchers from UCL in London concealed small amounts of explosives, including Semtex, C4, inside electrical devices such as hair dryers, laptops, and mobile phones. To closely resemble a traveler’s bag, the explosives were placed in bags with chargers, toothbrushes, and other everyday items.

While standard xray machines hit objects with an uniform field of xrays, the team scans the bags using a custom built machine that contains masks. These are sheets of metal with holes punched in them. They separate the beams into smaller beamlets.

Scans inside a bag. Top is conventional, bottom is microradian scatter technique
Scans inside a bag. Top is conventional, bottom microradian scatter.


As the beamlets passed through the bag and its contents, they were scattered at angles as small as a microradian (around one 20,000th as big as a degree).The scattering was analyzed by AI trained to recognize the texture of specific materials from a particular pattern of angle changes. Lead author Sandro Olivo from UCL Department of Medical Physics and Biomedical Engineering says that the AI is incredibly adept at picking up these materials, even when they are hidden within other objects. “Even if we hide a small quantity of explosive somewhere, because there will be a little bit of texture in the middle of many other things, the algorithm will find it.”

comparison between conventional and scatter technique
Conventional method (left) vs the scattering technique at right.


The algorithm was able to correctly identify explosives in every experiment carried out under test conditions, although the team acknowledged that it would be unrealistic to expect such a high level of accuracy in larger studies that resembled real-world conditions more closely.

The team believes that the technique could be used in medical applications, especially cancer screening. The researchers have yet to determine if the technique can distinguish the texture of a breast tumor from surrounding healthy tissue. However, the team is excited about the possibility of detecting small tumors that may otherwise go unnoticed behind a patient’s back. “I would love to do this one day,” he says. “If we can detect texture in tumors at a similar rate, the potential for early diagnosis of cancer is huge,” he says. But the human body is much more difficult to scan than static objects like bags. Kevin Wells, an associate professor at the University of Surrey was not involved in this study. Before it could be considered for human screening, researchers would have to reduce the size of the equipment and make sure that the cost is comparable to existing methods.

” The information presented here is very promising. He says that it has great potential to detect cracks and certain types of threats.

“For the medical, cancer-type application, it’s a possibility, but there are a few steps to go before you could demonstrate efficacy in a clinical context.”

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