In small-volume tumors, it is a radiotherapy technique that allows tumor cells to die or the tumor to shrink by giving high radiation energy only to this point at a time. Stereotaxy means identifying a target with the help of three-dimensional coordinates. This treatment method, in which a full dose is given at one time using stereotaxy, is also called Stereotactic Radio Surgery (SRC). In SRC, the tumor is completely destroyed in a single session with high-dose radiation following the determination of the coordinates in three dimensions. In this method, normal tissues around the tumor are protected from the harmful effects of radiation. The application of IGRT during this process is important for the actual destruction of the target.