The concept of spatial frequency depending DQE and its application to a comparison of two detectors used in transvenous coronary angiography
A comparison of two different multi-channel line detectors utilized in transvenous coronary angiography was performed. An Li+ drifted silicon strip detector (SSD) was tested at the SMERF facility X17B2 at the National Synchrotron Light Source (NSLS). An ionization chamber (IC) was tested at the W2 beamline at HASYLAB. Both detectors were operated in the charge-integrating mode. The main purpose was to measure and compare the Modulation Transfer Function (MTF( f)), Noise Power Spectrum (NPS( f)), Detective Quantum Efficiency (DQE( f)) in terms of spatial frequencies and the dynamic range of both detector systems. It turned out that the IC is superior to the SSD in time resolution and dynamic range at a single gain setting and has a slight advantage in the transmission of high spatial frequencies. Although for high photon flux the DQE values of the IC exceed those of the SSD, it is the reverse for low photon flux caused by a higher noise floor of the read-out electronics. This makes the SSD superior to the IC since the incident flux is limited by the tolerable entry dose to the patients. For the comparison other criteria like price, reliability, maintenance, etc., are not taken into consideration.