3-D conformal therapy is used to treat a variety of tumors by delivering a high dose to the target volume while minimizing dose to surrounding tissue. Conventional irradiation of intracranial lesions involves treating substantial portions of healthy brain. Stereotactic radiosurgery (SRS) delivers a single fraction to a small lesion targeted by an invasive head frame. The Laitinen stereoadapter is a noninvasive localization/immobilization device that provides the precision of stereotactic techniques (within 2 mm) with the radiobiologic advantage of fractionation. This report describes the Northwestern experience of 3-D conformal Stereotactic radiotherapy (SRT) for intracranial lesions using the Laitinen Stereoadapter for reproducible, noninvasive immobilization. 17 patients with 18 isocenters were treated with SRT via noncoplanar, static, and/or rotational beams. Patient age ranged from 3 to 77. Total doses ranged from 1000 to 5580 cGy at 180 to 400 cGy per fraction. Histologies included primitive neuroectodermal tumor (PNET), recurrent medulloblastoma, mixed germ cell tumor, recurrent juvenile pilocytic astrocytoma, optic glioma, oligodendroglioma, cran-iopharyngioma, meningioma, metastatic carcinoma, and one orbital rhabdomyosarcoma. Patient positioning was checked daily, and verification port films were taken every other day. Port films showed excellent reproducibility of isocenter placement with the Laitinen stereoadapter. Follow-up ranged from 1 to 24 months. Post-treatment radiographic responses were similar to those seen with conventional radiation therapy. The Laitinen stereoadapter is very well tolerated with minimal acute effects. Its use does not require excessive preplanning (i.e., customized oral appliances) and can accommodate any cranial size. Patients can initiate treatment within 24 hours, if necessary. The relocatable frame exploits the accuracy of SRS with the biological advantage of fractionation. We currently use the Laitinen for primary adult and pediatric brain tumors as well as metastatic lesions too large for SRS. Further studies are currently underway to further define its utility.