The current challenge from radiotherapy of early breast cancer has been to minimize the morbidity caused by this treatment without losing efficacy.Conventional two-dimensional radiotherapy breast plans can produce substantial dose inhomogeneities.Intensity-modulated radiotherapy(IMRT) can be used to improve the dose homogeneity in an irradiated volume.And to some extent,IMRT can reduce radiation doses to adjacent normal tissues including the contralateral breast,heart and lung,and improve the cosmetic outcome.