Evaluation of Effective Detective Quantum Efficiency with Digital Radiography to Optimize Exposure Condition for Chest Imaging

Effective detective quantum efficiency (eDQE) has recently been developed and introduced. The purpose of this study was to evaluate and optimize exposure conditions for chest imaging with digital radiography (DR) using eDQE. The exposure factors that we considered were tube potential and anti-scatter moving grid. The entrance air kerma was adjusted for each tube potential to yield an effective dose of 34 mu Sv. The scatter fraction (SF), transmission fraction (TF), effective modulation transfer function (eMTF), and effective normalized noise power spectrum (eNNPS) were measured using a phantom that simulates the attenuation and scatter properties of the human chest. Our results suggest that eMTFs are independent of tube potential regardless of whether or not a grid is used. The eNNPSs were greater with the use of an anti-scatter grid than without, while the eDQE was largest at lower tube potential when there was no grid. Our results indicate that the use of low tube potential without an anti-scatter grid is the most appropriate exposure condition for DR in chest imaging. Further research is needed to optimize measurement conditions for other types of imaging studies.