What is Stereotactic Radiosurgery? Stereotactic Radiosurgery (SRS) is a technique that delivers a high energy radiation dose to a lesion or other abnormality in the patient. X-Knife Stereotactic Radiosurgery uses computer images of the patients brain to accurately locate the volume of the brain containing the lesion to be treated. Treatment is carried out using a series of arcs of radiation, from a LINAC, which encompass the treatment volume while minimising the surrounding tissue and critical structures. A typical X-Knife treatment is completed in one day with the actual tratment taking about 30 minutes.