Unified MTF for scintillator-coupled CMOS sensor
- 作者：Kwang Hyun Kim ; Dong-Wan Kang ; Dong Ki Kim ; Yong-Kyun Kim
- 关键词：Unified MTF ; Scintillator-coupled CMOS sensor ; Digital radiography
- 刊名：Nuclear Instruments and Methods in Physics Research Section A ; Accelerators ; Spectrometers ; Detectors and Associated Equipment
- 出版年：2007
- 期刊代码：41_01689002
- 类别：ph
- 出版时间：21 August 2007
- 卷：579
- 期：1
- 页码：235-238
- 文件大小：268 K
摘要
The spatial resolution of scintillator-coupled CMOS sensor has been investigated from intrinsic sensor Modulation Transfer Function (MTF) to system MTF for the conditions of the digital radiography. For the intrinsic sensor MTF, the geometric MTF (gMTF) and the unified MTF (uMTF) were compared by analytic calculations for various pixel sizes. The effects of the initial dark signal of the sensor were considered in the calculation of the uMTF and reflected in a newly developed semi-empirical model. The measured system MTF and the calculated system MTF including semi-empirical model were compared under radiography conditions of 28 and 80 kVp. From the results, the calculated system MTF reflecting the dark-signal contribution on the sensor resolution did fit for the measured system resolution, and the higher the fraction of an initial dark signal to an output signal in response to X-ray exposure showed more degradation of the system resolution even with same scintillator and sensor.