by John R. Fischer
, Senior Reporter | December 20, 2021
While a necessary component for X-ray imaging, flat panels often lead to distorted edges in scans and do not allow for accurate registration of dose.
This is because the design for such devices is not efficiently matched with the complex shape and geometry of the human body. And designing alternative flexible detectors has not worked due to the rigid inorganic semiconductors used to make them.
But a new technique may offer the potential to change this, say researchers at the Advanced Technology Institute at the University of Surrey, who developed it with colleagues from the National Physical Laboratory and Sheffield University in the U.K. and University of Bologna in Italy.
Their approach consists of design rules for a special class of “inorganic in organic” semiconductors. With them, designers would be able to adjust the molecular weight of the bismuth oxide nanoparticle sensitized organ semiconductors to extend the length of the polymer chain. Not only would this help create more curved digital detectors but ones with high sensitivity that do not compromise image quality.
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"While flat panel detectors can perform well up to a certain point, they can lead to distortions and other aspects such as vignetting, which requires additional corrections. The use of curved detectors helps to bypass these issues and will hopefully lead to better diagnostics and treatment in medical imaging and cancer therapy and in many other sectors," Prabodhi Nanayakkara, lead author of the study and Ph.D. student at the University of Surrey, told HCB News.
The concept would enable curved detectors to be created by bending radii as small as 1.3 mm. Using organic or "inorganic in organic" semiconductors is also far more cost-effective than conventional inorganic semiconductors made from silicon or germanium, which require expensive crystal growth methods.
Detectors created with this technique would be scalable due to their design and the materials used to compose them, according to Nanayakkara. She and her colleagues have partnered with a spinoff company, SilverRay, to develop these flexible large-area detectors, which they expect will be useful in medical imaging and other X-ray-related industries, including security. For medical imaging, they see its potential in radiotherapy dosimetry and X-ray radiography on non-destructive testing.
Nanayakkara says commercialization would require the ability to scale-up this technology for imaging systems over very large areas. "At the moment our detector technology is presented in a single pixel format. It needs to be fabricated into a large area, multi-pixelated array and needs to be mounted with a readout electronic system. Following this, it needs to be tested for its suitability in each application, so we’re probably looking at another couple of years of research and development."
Earlier this year, scientists at the School of Basic Sciences in Switzerland’s École polytechnique fédérale de Lausanne (EPFL) crafted their own enhanced X-ray detectors with 3D printing
. Their high-resolution detectors were designed to be cost-effective and could be integrated into standard microelectronics to improve performance and reduce radiation exposure in medical imaging scanners.
For their approach, the Swiss researchers used aerosol jet-printing, a new 3D-printing technique used to manufacture electronic components, and made the detectors from graphene and perovskites. These materials have the potential to decrease required X-ray doses used to form images by more than a thousand times. The detectors were found to have record sensitivity and created a fourfold improvement in best-in-class medical imaging devices.
"It doesn't need sophisticated photomultipliers or complex electronics," said lead scientist professor László Forró. "This could be a real advantage for developing countries."