Curved digital X-ray detectors

• Main Authors: Albert J.J.M. van Breemen, Matthias Simon, Olivier Tousignant, Santhosh Shanmugam, Jan-Laurens van der Steen, Hylke B. Akkerman, Auke Kronemeijer, Walter Ruetten, Rob Raaijmakers, Lex Alving, Jan Jacobs, Pawel E. Malinowski, Florian De Roose, Gerwin H. Gelinck
• Format: Article
• Language: English
• Published: Nature Publishing Group 2020-09-01
• Series: npj Flexible Electronics
• Online Access: https://doi.org/10.1038/s41528-020-00084-7

Abstract 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 cm2 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/cm2 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.