Localization of the surgical bed using supine magnetic resonance and computed tomography scan fusion for planification of breast interstitial brachytherapy

Supine breast MRI yields a more precise definition of the SB with a smaller inter-observer variability than CT and may obviate the need for surgical clips. The volume of the SB is smaller with MRI. In our opinion, CT-MRI fusion should be used for SB delineation, in view of partial breast irradiation.