Plot of cumulative absolute risk of radiation induced breast cancer as a function of attained age for a 20 year old female patient. The triangles represent the data from Hodson et al.  for mantle field irradiation in comparison with the modelled data for 40 Gy as the solid line. The dotted line marks mediastinal IFRT with the prescribed dose of 40 Gy. A volume reduction with 40 Gy INRT is shown as the dashed line and an additional dose reduction to 30 Gy is represented by the dashed-dotted line. Baseline risk is plotted as the diamonds.