Characterization of Flexible Amorphous Silicon Thin-Film Transistor-Based Detectors with Positive-Intrinsic-Negative Diode in Radiography

Abstract

Low-dose exposure and work convenience are required for mobile X-ray systems during the COVID-19 pandemic. We investigated a novel X-ray detector (FXRD-4343FAW, VIEWORKS, Anyang, Korea) composed of a thin-film transistor based on amorphous silicon with a flexible plastic substrate. This detector is composed of a thallium-doped cesium iodide scintillator with a pixel size of 99 μm, pixel matrix of 4316 × 4316, and weight of 2.95 kg. The proposed detector has the advantages of high-noise characteristics and low weight, which provide patients and workers with an advantage in terms of the dose and work efficiency, respectively. We performed a quantitative evaluation and an experiment to demonstrate its viability. The modulation transfer function, noise power spectrum, and detective quantum efficiency were identified using the proposed and comparative detectors, according to the International Electrotechnical Commission protocol. Additionally, the contrast-to-noise ratio and coefficient of variation were investigated using a human-like phantom. Our results indicate that the proposed detector efficiently increases the image performance in terms of noise characteristics. The detailed performance evaluation demonstrated that the outcomes of the use of the proposed detector confirmed the viability of mobile X-ray devices that require low doses. Consequently, the novel FXRD-4343FAW X-ray detector is expected to improve the image quality and work convenience in extended radiography.

Development of Adaptive Point-Spread Function Estimation Method in Various Scintillation Detector Thickness for X-ray Imaging

“…This depends on the shape of the pulse-height distribution in the X-ray phosphors. Therefore, direct conversion detectors have a relative advantage for high-resolution imaging, such as mammography [13,14], and it is helpful to improve the image quality by optimizing the scintillator thickness for optimal detection quantum efficiency (DQE) with noise reduction, although the resolution and sharpness are reduced [15,16].…”

Investigation of Deconvolution Method with Adaptive Point Spread Function Based on Scintillator Thickness in Wavelet Domain

“…Sensitivity can be improved by increasing the thickness of the indirect conversion-type X-ray detector. However, thick X-ray detectors result in a decrease in spatial resolution, and a method is required to address this [9]. Thus, the deconvolution method has been introduced as an approach for improving resolution.…”

Optimization Method to Predict Optimal Noise Reduction Parameters for the Non-Local Means Algorithm Based on the Scintillator Thickness in Radiography

“…The fact that the diagnosis should be made while maximally reducing patient exposure according to the “as low as reasonably achievable” (ALARA) principle [ 10 ] contributes to the consideration of the use of thick scintillators so that the information of the detected radiation can be significantly reflected in the actual image. However, an increase in the scintillator thickness has a trade-off relationship in terms of reducing the image resolution [ 11 ]. As the scintillator thickness increases, the amount of light relative to the detected radiation increases.…”