[Quantitative evaluation of magnetization transfer ratio in irradiated breast with breast conservation therapy]

To assess the late effects of radiotherapy, magnetization transfer was evaluated in 2 patients with breast conservation treatment and in 4 patients without treatment. The magnetization transfer ratios (MTRs) were measured from a pair of images obtained by the conventional SPGR pulse sequence and the MT-prepared SPGR sequence on a 1.5-TMR system. The MTR values of irradiated breast were higher than those of non-irradiated breast. The difference in MTR between them was considered to represent tissue change due to irradiation. We showed that MTR is a useful parameter in estimating the late effects of radiotherapy.