Objectives:Treatment of arterivernous malformation(AVM)of the brain is challenging due to the size and location of the nidus-proper and its proximity to the cerebrovascular.Accurate target delineation has significant impact on intracranial AVM obliteration and potential complications of stereotactic radiosurgery.Method:we used the contrast CT 3DXA MRA(3D-TOF)and DTI images when do the AVM ck treatment planning.All the studies in DICOM format,fused CT,MRA,DSA and DTI.Delineated AVM target including AVM nidus,embolization parts,small draining vein in the 3DXA and MRA,avoiding the fiber tracts showed in DTI images,if target located thalamic and basal ganglia,meanwhile delineated the fiber tracts as OAR.Limited fiber tract dose,fewer high dose in large draining vein.2-3 fractions,with 65%-70%isodose line to cover the AVM margin.Margin dose was 18-28Gy Result:AVM delineation process is slightly longer due to the many projections.The benefit is forming real sstrcuture volume on the planning CT.AVM obliteratin was confirmed by MRI and angiography.Conclusions:Multi-image modality could give more informations of target and fiber tract.Cyberknife radiosurgery with multu-image modality offer more accuracy in delineation the target,improving the treatment efficacy,reduing the adverse radiation effects.