A method for material decomposition in dual-energy contrast enhancement digital mammography

Background and purpose: Dual-energy mammography is a technique which is being used for accuracy enhancement of the breast cancer diagnosis especially in dense breasts. It is also a valuable and practical way for obtaining detailed information about tumor’s size, disease progression and micro-calcification detection which is the earlier sign of breast cancer. The aim of this study was to investigate the possibility of separating different thicknesses of micro-calcifications, Iodine, and Bismuth contrast agents, simultaneously.Material and methods: A breast phantom was made from acrylic and olive oil containing various density thicknesses of Iodine and Bismuth contrast agents. To simulate micro-calcifications, different thicknesses of the Aluminum sheets were used and placed in the phantom as well. In this work, an X-ray tube with Tungsten anode and a flat panel semiconductor detector were used for imaging processes. To customize the X-ray spectrum, a combination of copper and aluminum were used as filters to optimize the X-ray high energy spectrum in dual energy imaging.Results: According to the results, separating of Iodine images was prepared by using of Iodine’s k-edge property for thicknesses greater than 0.5 mg/cm2. Also, Bismuth and Aluminum images with thicknesses greater than 0.53 mg/cm2 and 200 μm, respectively, were isolated automatically by material thicknesses estimation method in dual-energy imaging technique.Conclusion: The results demonstrated that Iodine and Bismuth contrast agents together with micro-calcifications can be separated from breast tissue with good accuracy by using proposed dual-energy contrast enhanced mammography technique.