25 May 2022

Curved X-ray detectors for safer radiation therapy

curved NP-BHJ X-ray detector held with a tweezer

Researchers at the University of Surrey have identified key design rules for making curved X-ray detectors, bringing clearer and safer X-rays a step closer to reality.

Although the use of digital flat panel detectors has enabled radiographers to examine X-rays much more quickly compared with old-fashioned X-ray sensitive photographic films and to make quicker diagnoses, flat panels are ill-suited to the complex shape and geometry of the human body. The reliance purely on flat panels means there is unavoidable distortion around the edges of images. Flat panels also prevent an accurate registration of the X-ray dose delivered, a key feature towards enabling safer radiation therapy and minimising secondary tumours.

Efforts to create flexible detectors have so far been unsuccessful, owing to the brittle characteristics of the rigid inorganic semiconductors used to make them. Some curvature has been achieved through using a thinner layer of semiconductor, but this has compromised performance levels and resulted in poor quality images.

Now, researchers from the Advanced Technology Institute at the University of Surrey, in collaboration with Italy’s University of Bologna, the National Physical Laboratory and Sheffield University, have identified design rules for a special class of “inorganic in organic” semiconductors. By tuning the molecular weight of the bismuth oxide nanoparticle sensitised organic semiconductors to lengthen the polymer chains, the researchers are paving the way towards making more robust, curved digital detectors with high sensitivity, or digital film.

Professor Ravi Silva, Director of Surrey’s Advanced Technology Institute, said: “The technology will help create a revolutionary new high sensitivity X-ray detector that is scalable, due to the design and materials adopted. This technology has huge potential in medical applications and other X-ray uses, so we’re working with a spinout company, SilverRay, and hope to turn this technology into the X-ray detector of choice for high sensitivity, high resolution, flexible large area detectors.”