X-ray performance of a wafer-scale CMOS flat panel imager for applications in medical imaging and nondestructive testing

摘要

This paper presents a wafer-scale complementary metal-oxide semiconductor (CMOS)-based X-ray flat panel detector for medical imaging and nondestructive testing applications. In this study, our proposed X-ray CMOS flat panel imager has been fabricated by using a 0.35 μm 1-poly/4-metal CMOS process. The pixel size is 100 μm × 100 μm and the pixel array format is 1200 × 1200 pixels, which provide a field-of-view (FOV) of 120mm × 120 mm. The 14.3-bit extended counting analog-to digital converter (ADC) with built-in binning mode was used to reduce the area and simultaneously improve the image resolution. The different screens such as thallium-doped CsI (CsI:TI) and terbium gadolinium oxysulfide (Gd_2O_2S:Tb) scintillators were used as conversion materials for X-rays to visible light photons. The X-ray imaging performance such as X-ray sensitivity as a function of X-ray exposure dose, spatial resolution, image lag and X-ray images of various objects were measured under practical medical and industrial application conditions. This paper results demonstrate that our prototype CMOS-based X-ray flat panel imager has the significant potential for medical imaging and non-destructive testing (NDT) applications with high-resolution and high speed rate.