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 30 X 40 cm2 dynamic flat detector (FD) compared to state-of-the-art IITV technology. A Trixell detector for vascular and RF applications is designed for a mixed use of fluoroscopy as well as exposure series and a range of radiographic applications. An RF system has been built which comprises both the FD as well as an IITV detector. This system enables a direct comparison of technical image quality measurements and patient images under exactly the same X-ray conditions. Image quality measurements comprise Detective Quantum Efficiency including transfer characteristics, Modulation Transfer Function, Noise Power Spectrum, lag, Low Frequency Drop and residual signals. Observation tests, using Threshold Contrast Detail Detectability (TCDD) techniques, are performed in order to confirm the results of the technical measurements. Results show a DQE (f) of the flat detector that is higher compared to IITV and above all constant over a wide dose range, the IITV DQE (f) drops at higher dose range due to fixed structure. Furthermore the Low Frequency Drop is substantially smaller in the FD-based system. The TCDD subjective tests show improved system performance in favor of the FD system.