Objective:Use SWI to analysis imaging change in the patients with brain metastasis treated by radiotherapy.Methods:Fifteen patients with brain metastasis from pathologic confirmed lung cancer were treated by LINAC radiosurgery in combination with WBRT.All cases were underwent examination of SWI before treatment,1 day,1 week,1 month,3 months and 6 months after treatment.The changes of vessels of tumor were viewed.Results:Vessels and hemorrhage could be seen in 36 focuses.The vessels were decreased at the first day after radiosurgery.And the number of vessels decreased followed the volume of the tumor as the time delay.Conclusions:It was useful for the patients with brain metastasis treated by radiotherapy to obeserve the vessels change in tumors with SWI.And it could make a basis for the deepen study.