Curved digital X-ray detectors

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.

Applications for Flexible TFT Arrays Emerge in the Biomedical Domain

“…The prototype was integrated into a medical cone‐beam computed tomography system. Curved x‐ray detectors provide a more compact imaging x‐ray system with better and more uniform 3D image quality 1,2 …”

“…X‐ray imaging with (flexible) thin‐film transistor (TFT) arrays 1,2 . (a) What most medical offices use currently—a rigid and heavy flat panel using glass for x‐ray detection.…”

6‐1: Invited Paper: Measuring Health Parameters with Large‐Area Organic Photodetector Arrays

“…Recently, we reported a prototype curved x-ray detector that was integrated into a medical cone-beam CT (CBCT) system. The curved detector resulted in a more compact 3D imaging x-ray system with better, more uniform image quality [7].…”

Ultra‐Stable and Robust Response to X‐Rays in 2D Layered Perovskite Micro‐Crystalline Films Directly Deposited on Flexible Substrate

“…In particular, the development of light and flexible devices would represent a major breakthrough in the field, as it allows new detector design and applications, for example, portable real‐time X‐ray dosimeters or curved digital X‐ray imagers. [ 1 ] Exposure to high doses of X‐rays increases the risks of developing radiation‐induced disorders such as cancers [ 2 ] and enhancing the detection limit of detectors is a critical key issue for medical application, since it would help reducing the radiation dose delivered to the patient and therefore limit the radiation hazards linked to radiation therapy and diagnostics (e.g., mammography, X‐ray tomography). The specifications cited above call for the development of solution‐processable X‐ray direct detecting materials compatible with low‐temperature deposition on flexible plastic substrates, and in addition capable of working at low radiation doses.…”