Imaging for early stage breast cancer

Comparison of effective target volume between MammoSite and 3D CRT

Problem: different cavity expansion used depending on technique, MammoSite 1.0 cm, 3D CRT 1.5 cm. Previously stated that this is effectively equivalent. But is that true? 10 pts treated with MammoSite, CT scan before and after balloon implantation Deformable registration was used to deform the MammoSite CTV onto the balloonless CT scan. This takes into account asymmetric cavity and that tissue arund the MammoSite is stretched during inflation of balloon

CTV effective

MammoSite with CTV, 1.0cm margin

Effective CTV generated by deforming the MammoSite CTV onto the pre-MammoSite CT. Arrows indicate anatomical features for accuracy

Shaitelman et al, IJROBP, 2012