Image quality of a large area dynamic flat detector: Comparison with a state-of-the-art II/TV system

The purpose of this research is to establish the technical and clinical image quality of a 30x40 [cm(2)] dynamic medical x-ray flat detector (FD) compared to state-of-the-art Image Intensifier Television (II/TV) technology. The detector used was a Trixell Pixium 4700 designed for vascular and RF applications such as mixed fluoroscopy and radiography examinations. An RF system has been built which comprises both the FD, as well as an II/TV detector. This system enables a direct comparison of technical image quality measurements and patient images under exactly the same x-ray conditions. Comparison of clinical examinations on individual patients or groups of patients are possible. Image quality measurements performed comprise Detective Quantum Efficiency (including Modulation Transfer Function and Noise Power Spectrum), Disk Transfer Function and temporal artifacts. Observation tests, using Threshold Contrast Detail Detectability (TCDD) techniques, were also performed. Results show a DQE of the flat detector that is higher compared to II/TV and, above all, constant over a wide dose range. The II/TV DQE drops at higher dose range due to fixed pattern noise and CCD shot noise. Furthermore veiling glare (or flare) is substantially smaller in the FD-based system. TCDD subjective tests show improved system performance in favor of the FD system.