Curved digital X-ray detectors

• Published in: Npj flexible electronics Vol. 4; no. 1; pp. 1 - 8
• Main Authors: van Breemen, Albert J.J.M., Simon, Matthias, Tousignant, Olivier, Shanmugam, Santhosh, van der Steen, Jan-Laurens, Akkerman, Hylke B., Kronemeijer, Auke, Ruetten, Walter, Raaijmakers, Rob, Alving, Lex, Jacobs, Jan, Malinowski, Pawel E., De Roose, Florian, Gelinck, Gerwin H.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.09.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 639/166; 639/925; Backplanes; Cesium iodides; Chemistry and Materials Science; Computed tomography; Curved beams; Dark current; Digital imaging; Electronics and Microelectronics; Foils; Gallium; Gantry cranes; Image quality; Image reconstruction; Indium gallium zinc oxide; Instrumentation; Materials Science; Nondestructive testing; Optical and Electronic Materials; Optical measuring instruments; Polymer Sciences; Quantum efficiency; Scintillation counters; Sensors; X ray detectors; X ray imagery; Zinc oxide
• ISSN: 2397-4621; 2397-4621
• DOI: 10.1038/s41528-020-00084-7

A curved image sensor on plastic foil has been developed for cone beam computed tomography (CBCT) X-ray imaging. The image sensor of about 6 × 8 cm 2 size has been built on a thin polyimide foil with an indium gallium zinc oxide (IGZO) backplane and an organic photodetectors (OPD) frontplane. A flexible cesium iodide (CsI) scintillator has been attached to the optical sensor with 480 × 640 pixels of 126 µm size. Dark current density of the OPD was low with less than 10 −7  mA/cm 2 at −2 V, while an external quantum efficiency (EQE) of about 50% was reached in the visible wavelength range matched to the scintillator output. The image quality of the digital X-ray detector allowed for 3D reconstruction images of a bone phantom on a rotating stage with a lab setup. The curved detector with 32 cm curvature radius opens up the path for very compact CBCT gantries with largely reduced footprint.