4D-CT respiratory temporal fusion control technique is a technique used to mitigate the effects of respiratory motion. Tumors in the lungs of lung cancer patients have a very obvious position movement during respiration, and the magnitude of the movement is significant, even more than 2 cm in some cases. 4D-CT respiratory temporal fusion control technique has a great potential benefit for lung cancer treatment, especially for early stage lung cancer. Because the magnitude of respiratory motion cannot be directly predicted, a sufficiently large border around the CTV in the clinical target area is often flared in order to compensate for the effect of respiratory motion, but the tumor movement is different from patient to patient, and because the tumor motion due to respiratory motion is almost linear, the flare in all directions of the CTV can lead to more unnecessary irradiation of lung tissue and cause more severe radiation pneumonia. With the introduction of 4D-CT image technology in lung cancer radiotherapy, tumor motion within the lung is tracked during the respiratory cycle, and the effect of respiratory motion is accurately compensated for during the outlining of the ITV in the inner target area, thus reducing the treatment area. By controlling the radiation emission through the respiratory temporal fusion control technique, the treatment area can be further reduced and the irradiation to the lung tissue can be reduced. Conversely, if the irradiation range can be reduced, then the dose to the tumor can be increased without increasing the amount of normal tissue irradiated compared to not implementing the respiratory temporal fusion control technique. However, even if the tumor external radiation border is not reduced, the respiratory time-fusion control technique radiotherapy can result in a reduction of the lung volume entering and leaving the high dose area, thus reducing the amount of normal lung tissue irradiated and contributing to a better protection of normal lung tissue. It should be noted that to improve the quality of breath-time phase fusion control technique radiotherapy for lung cancer, it is also necessary to incorporate measures to reduce positional errors and ensure quality control. The use of 4DCT breath-time fusion control technique allows patients to breathe freely during positioning scans and treatment, unlike other breath control techniques that require patients to hold their breath. The use of 4DCT respiratory temporal fusion control in combination with a spiral tomotherapy system (Tomo) for lung cancer radiation therapy can achieve better outcomes for lung cancer.