Image Guidance in External Beam Accelerated Partial Breast Irradiation: Comparison of Surrogates for the Lumpectomy Cavity

Use of either breast surface or surgical clips as surrogates for the cavity results in improved localization in most patients compared with bony registration and may allow smaller planning target volume margins for external beam accelerated partial breast irradiation. Compared with surface registration, clip registration may be less sensitive to anatomic characteristics and therefore more broadly applicable.