The Central Research Institute of Roentgenology and Radiology and the Research and Production Complex, Radiation Training Center, D. V. Efremov Research Institute of Experimental Physics have been the first in Russia to design a narrow photon-beam unit for stereotactic radiation therapy of intracranial small formation. Fifty one patients were treated. Thirty six presented arteriovenous malformations, 4 had hypophyseal adenomas. The hypophysis was exposed to radiation in 11 patients with prostatic cancer. The unit has been found to have great operational and clinical capacities.