Simulating mammographic absorption imaging and its radiation protectionproperties

摘要

There is a large number of optimization strategies for optimal relation between information and exposure in mammographic imaging procedures. This is especially due to the specific situations in screening programs. However, the variety of possibilities like breast CT, tomosynthesis absorption with photon counting or with energy integrating detectors and phase contrast mammography results in very difficult comparisons about pros and cons of different techniques. Simulation methods based on Monte-Carlo methods would be a useful tool for first approaches. However, such a simulateion approach requires suitable and useful phantoms of the female breast in typical imaging conditions. Voxel phantoms of real breasts would be an optimal solution. Mammographic specimen of female breasts from corps have been compressed and than fixated while being compressed as in a general mammographic application. Such kinds of specimen have been scanned using a flat panel imager system a holding unit and a rotation table. By that CT images could be gained with relatively low radiation qualities. These data sets have been transformed by segmentation into high resolution voxel models. We performed Monte-Carlo simulations of using such phantoms for simulating absorption based imaging procedures including monoenergetic and standard spectra images using EGSnrc and Geant4 codes to proof the feasibility of such phantoms and simulations in order to obtain a tool for radiation protection optimization.