ABSTRACT
Since the 1950s, the stereotactic principle has been adopted by neurosurgeons, and the first dedicated unit for stereotactic radiosurgery (SRS) known as the Gamma Knife (Elekta AB, Stockholm, Sweden) was developed by a Swedish neurosurgeon. The transition of “frame” to “frameless” brain radiosurgery is discussed in this chapter with respect to the influence of evolving technology including the changes in immobilization systems. A stereotactic localizer can be utilized for setting the patient up to the treatment isocenter. A few varieties of these noninvasive relocatable frames are described, and they include the Gill–Thomas–Cosman (GTC) frame, the BrainLAB mask system, and the Laitinen Stereoadapter 5000 frame. Frame-based SRS using localizer or fiducial boxes enable accurate setup of patients without the need for patient setup verification images. With invasive frames, patients can be immobilized accurately to less than 1 mm setup errors.
