Brain tissue is surrounded by a dense skull, and a lesion in a certain part of the skull can only be diagnosed based on the patient’s symptoms and signs and the necessary instrumental examinations. The invention and development of modern medical imaging technology, such as CT, MRI, DSA, PET-CT, magnetoencephalography, etc., have made the diagnosis of cranial and cerebral diseases relatively easy, and have clarified the location and even the nature of the lesion, which has provided an objective basis for the choice of treatment, especially for the choice of operation, and has made neurosurgery more and more safe. However, for those special surgeries such as deep brain nuclei, smaller lesions and biopsy of lesions, a method of precisely determining intracranial foci (target points) is needed in order to achieve the purpose of precise surgical operation and minimize the damage to normal brain tissues. The creation and development of brain stereotactic technology better solves this problem. Brain stereotactic technology was first created in 1908 by Horsley and Clarke, who introduced a device that, when fixed to anatomical landmarks, allowed precise fixation of electrodes in the brains of experimental animals, and described how to accurately place the electrodes for brain localization mapping techniques. They also coined the term “stereotactic”, which is derived from the Greek letters stereo (meaning three-dimensional) and taxic (meaning systematic or arranged). 1945 saw the first ever stereotactic brain mapping of the human brain, accomplished by the American scholars Spiegel and Wycis. In 1945, American scholars Spiegel and Wycis performed the first stereotactic surgery on a human brain. Later on, scholars such as Riechert of Germany, Talairach of France, Cooper of the United States, and Sugita of Japan made important contributions to the development of brain stereotactic technology. In particular, the Swedish neurosurgeon and inventor Prof. Lars Leksell (Figure 1-1) invented a brain stereotactic apparatus in 1950, and inspired by its clinical use, he put forward the concept of stereotactic radiosurgery (SRS) in 1951, and invented the Gamma Knife, pioneering the development of stereotactic brain surgery. Leksell’s stereotactic instrument has also become more and more perfect, and has become the classic brain stereotactic instrument (Figure 1-2), which is still widely used in the clinic. The principle of stereotactic orientation is to establish a three-dimensional coordinate system in the patient’s head, and the center point of the coordinate system is 0 point. According to the principle that only one point can be determined by the intersection of three planes, each point in the brain is determined by the three-dimensional coordinate values of X, Y, and Z. The three-dimensional coordinate system is established precisely because of the intersection of three planes. The establishment of the three-dimensional coordinate system is precisely realized by the brain stereotactic apparatus. The brain stereotactic technique consists of two aspects, one is localization and the other is guidance. Localization is to accurately determine the three-dimensional coordinate values of X, Y, Z of intracranial lesions or targets.Before the 1970s, target localization was mainly based on extrapolating the three-dimensional coordinates of invisible targets by using some anatomical landmarks and bony landmarks shown by X-ray ventriculography, which was mainly used for the treatment of some functional disorders, such as tremor paralysis. After the seventies, CT and MRI were introduced one after another, and brain stereotactic instrument was combined with them, after the patient’s head was installed with the directional instrument and scanned with CT or MRI, the computer could calculate the three-dimensional coordinates of any point in the brain (the target point), X, Y, Z. The target point was both intuitive and precise, which made the stereotactic brain surgery easier and safer, and the advantages were more obvious, and the scope of application was also further expanded. Guiding is the precise introduction of surgical instruments to a predetermined lesion (target point) for surgical operation according to the three-dimensional coordinate values X, Y, Z. The target point is intuitive and precise, making brain stereotactic surgery easier and safer, and further expanding the scope of application.