The aim of this work was to evaluate the reliability of the square of the signal-to-noise ratio rate, SNR 2rate, as a precise measurement for quality control test in a digital fluoroscopy system. The quasi-ideal model observer was used to measure SNR 2rate. The dose rate, pulse rate and field of view were varied, and their effect on dose efficiency, defined as SNR 2rate/ P KA,rate, was evaluated (where P KA,rate is the air kerma-area product rate). Measurements were repeated to assess reproducibility. The relative standard deviation in SNR 2rate/ P KA,rate over seven consecutive measurements was 5 %. No significant variation in SNR 2rate/ P KA,rate was observed across different pulse rates (10–30 pulses s−1). The low-dose-rate setting had a superior dose efficiency compared with the medium- and high-dose-rate settings. A smaller field of view resulted in higher dose efficiency.
The results show that SNR 2rate/ P KA,rate measurements offer the high precision required in quality control constancy tests.