Clinical evaluation of interfractional variations for whole breast radiotherapy using 3-dimensional surface imaging

Daily alignment with 3D surface imaging was found to be valuable for reducing setup errors when comparing with patient alignment from skin marks. The result of the surface-based alignments specifically showed that alignment with skin marks was noticeably poor in the anteroposterior directions. The overall dosimetric effect of the interfractional variations was small, but these variations showed a potential for increased dose deposition to both the heart and lung tissues. Although these interfractional variations would not negatively affect the quality of patient care for whole breast radiotherapy, it may require an increase in PTV margin, especially in cases of partial breast irradiation.