Radiotherapy, as one of the three major means of tumor treatment, plays an irreplaceable role in the treatment of tumors. With the in-depth research on tumor treatment methods and the innovation of medical imaging technology brought by the rapid development of computer technology, various complex treatment techniques have been promoted and commonly applied in clinical practice, and at the same time, higher requirements for the precision of treatment have been put forward. As we know, the purpose of radiation therapy is to maximize the dose to tumor tissue and minimize the dose to normal tissue. Since the emergence of various advanced medical imaging technologies provides the possibility and reliability of accurate depiction of human tissues and organs, it also provides great help for radiation therapy physicians to precisely outline tumors. Based on this, we can form a “peak” shaped dose distribution around the tumor with the required high dose gradient by using advanced treatment methods such as conformal therapy technology and intensity modulation technology, where the high dose area surrounds the tumor and normal tissues receive little dose contribution, thus providing “precise” irradiation to the tumor. This allows for “precise” irradiation of the tumor. But how do you ensure that the treatment is “precise”? IGRT is a four-dimensional radiotherapy technique, which adds the concept of time factor to the three-dimensional radiotherapy technique, taking into account the movement of anatomical tissues during treatment and the displacement errors between treatment sessions, such as breathing and peristaltic movements, daily positioning errors, target area contraction, etc. The treatment conditions can be adjusted according to the changes of the organ position so that the irradiation field can closely follow the target area and achieve a truly precise treatment. The IGRT technology is currently being used. Several IGRT techniques are currently in use, including the use of ultrasound equipment, treatment room CT, gas pedal CT, volumetric CT and CT gas pedals (tomotherapy), as well as the use of matched X-ray imaging systems on gas pedals and electronic projection imaging systems (EPID) for position and dose intensity verification at each treatment. The linear gas pedal will be the first radiotherapy device to use IGRT (image guided radiation therapy) technology, which will enable physicians to achieve the precise radiotherapy required to achieve more effective control and treatment of tumors, especially in the chest and abdomen, while reducing the occurrence of side effects.