An Analysis and Evaluation Method for Imaging Noise in Dual-Energy Digital Mammography

Since the results of dual-energy digital mammography(DEDM) are always influenced by image noise,a new algorithm is presented to evaluate the imaging noise effects and is verified on clinical systems.A breast phantom is exposed using the dual-energy(DE) technique on two clinical systems and then the imaging noise is calculated.A sensitivity formula of DE calcification signal to imaging noise is deduced based on DEDM physical model and is used to evaluate sensitivities.Imaged breast with different calcification clusters is simulated and a calcification image is generated by using an inverse-map function.With this proposed algorithm,evaluations are performed by comparing the root-mean-square of calcification signal fluctuations in background regions with the contrast-noise-ratio of calcification signals in clusters.The simulation results show that the imaging noise has a big impact on DEDM calcification signals,and causes 100~120 μm calcification signal fluctuations on GE Senographe Essential system and 160~200 μm fluctuations on GE Senographe DS system.It shows that the essential system is more effective in DEDM.