Gamma Knife is not a real scalpel, but also a kind of radiation therapy, its full name is Stereotactic Gamma Ray Radiation Therapy System, which is a kind of modern large-scale high-tech medical equipment integrating modern radiophysics, radiobiology, medical imaging, computers, intelligent automated control and other disciplines. It adopts geometrical focusing way of r-rays radiated by radioactive element 60Co, and through precise stereo orientation, a certain dosage of gamma rays will be irradiated in the tumor centrally after planning, so as to destroy the tumor tissues with one-time lethal dosage to achieve the same effect as that of surgical resection or local destruction. Due to the rotational focusing of the rays, the normal tissues of the human body are only exposed to instantaneous, almost harmless irradiation, and the dose is sharply reduced, so its therapeutic irradiation range and the normal tissue boundaries are very obvious, and the edges are as neat as a scalpel cut, so it is imaginatively called the Gamma Knife.
The therapeutic principle of Gamma Knife is similar to the focusing process of a magnifying glass, which is placed in the sunlight, and the magnifying glass will become a dazzling spot of light that is the focal point. Outside of the focus, the person feels as normal, but at the focus there is a high level of heat, enough to set some objects on fire. Thus, the radiation dose is focused on the tumor area so that the tumor receives a dose high enough to kill the tumor, thus achieving the desired therapeutic effect.
But Gamma Knife is not a complete replacement for surgery or traditional oncology, and it is more suitable for treating regularly shaped and relatively small tumors. Therefore, for liver cancer, Gamma Knife is suitable for small liver cancers that cannot be surgically resected or locally ablated.