Cranial gamma knife mainly consists of 60Co (cobalt 60) radioactive source, collimator, treatment bed, stereotactic frame, computerized treatment plan design system, computerized operation control system, etc. 60Co radiation source: There are five isotopes in the cobalt element family, namely 56Co, 57Co, 58Co, 59Co and 60Co, except for 59Co which is a stable isotope (non-radioactive), the rest are radioactive. Among them, 60Co is a kind of nuclear radiation element with strong penetrating power. Medical science uses 60Co radiation penetration to kill tumor cells inside the body. Cranial gamma knife in the number of cobalt sources and geometric arrangement has its own characteristics, the application of dozens of hundreds of low-energy 60Co sources, arranged in a hemispherical geometric distribution (different cranial gamma knife in the cobalt source arrangement differs, as discussed later in the Q&A), so that each source points to the same round point, that is, the focus. Collimator: This is the steel device that directs each beam of 60Co radiation, i.e. gamma rays, precisely to the focus point. The shape of the collimator is hemispherical, except for the Massive Gamma Knife collimator, which is cylindrical. The number of collimators varies from one gamma knife to another, and the Leksell Gamma Knife has four collimators of different apertures, which are cumbersome to use and have to be replaced as needed during treatment. While the Ovo cranial gamma knife, Masip cranial gamma knife, Zunrui cranial gamma knife only need a collimator of different aperture sizes, a higher level of automation, treatment without human replacement, the computer automatically replaced according to the treatment plan. Treatment bed: The treatment bed is the device that fixes the patient according to the requirements of the treatment plan and sends the patient into the gamma knife irradiation field for treatment. It is worth mentioning that the Zunrui Gamma Knife treatment bed and the mainframe are integrated steel connection, which ensures that the treatment bed and the mainframe are never deformed and may have displacement, thus ensuring the accuracy of treatment precision. Stereotactic frame: It is a device to precisely determine the cranial lesion. All are classic Leksell type positioning frame, generally divided into CT type and MRI type, only Zunrui Gamma Knife stereotactic frame two in one, only one stereotactic frame can meet the needs of CT and MRI positioning, without the need to replace. Treatment plan design system: this is a very important component, if the above-mentioned parts are hardware, then this part is the software, and the software is the fastest development and update. With the development of computer technology, the gamma knife treatment plan design system is more automated, programmed, but also greatly improved the efficiency and radiation dose distribution accuracy. Operation monitoring system: monitoring system is to ensure that the gamma knife in accordance with the treatment plan to implement treatment, and to ensure the safety of treatment system. There are many linked systems, if there is a problem in one part of the treatment, the gamma knife will not be able to implement the treatment, or automatically terminate the treatment.