Intensity-modulated radiation therapy refers to the adjustment of the output dose at various points in the cross-section of the irradiated field in the required manner on the basis of three-dimensional conformal irradiation, so that the spatial distribution of radiation dose in the body is consistent with the lesion after rotational irradiation, forming a high-dose area. This not only makes the target area receive a higher dose of irradiation, which improves the tumor control rate, but also reduces the amount of surrounding normal tissues, reduces the damage to normal tissues and improves the quality of life of patients. Intensity-modulated conformal radiation therapy is the most advanced radiation therapy technology for tumors, and only a few tumor treatment centers in China can carry out it.