Nasopharyngeal cancer is one of the common malignant tumors in China, and its incidence rate accounts for the first place of head and neck malignant tumors. The World Health Organization estimates that 80% of the world’s nasopharyngeal cancer patients are in China. Many patients hesitate between surgery and radiotherapy and chemotherapy after the disease, so much so that they miss the best treatment time. Of course, after listening to many doctors’ presentations of different options, there are also many patients who have doubts about the options of radiation oncologists: why should radiotherapy be preferred for nasopharyngeal cancer? Why should radiotherapy be preferred for nasopharyngeal cancer? Nasopharynx, also known as epiglottis, is located in the upper 1/3 of the pharynx, between the base of the skull and the soft palate, connecting the nasal cavity and oropharynx, and is a key passage for breathing. The nasopharyngeal cavity consists of six walls, shaped like a domed hexagon; the walls are “each in their own way” and The nasopharyngeal cavity is composed of six walls, which are shaped like a circular arch hexagon; the walls are “each in its own way” and lap each other. If there is tumor invasion, any one of them will easily cause lesions. Meanwhile, there are many important organs adjacent to the nasopharynx; the upper part is connected to the skull base, and there are many pairs of cerebral nerves penetrating from the back to the front; the lower part is connected to the cervical vertebrae and pharyngeal constriction muscles and pharyngeal fascia. On the other hand, as a dynamic risk factor, the nasopharyngeal lymphatic network is extremely rich, thick and crossed from left to right. In view of such complex anatomy, it is difficult to provide good surgical conditions in the nasopharynx; and most of the nasopharyngeal cancers are low-differentiated squamous cancers with high sensitivity to radiation. Therefore, radiotherapy has been the preferred method to treat nasopharyngeal cancer. There is another reason why many patients are reluctant to choose radiotherapy – they are afraid of the so-called side effects: dry mouth, difficulty in opening mouth, muscle fibrosis …… In fact, this is because of the traditional “high dare not high, low dare not low” treatment. In fact, this is because the side effects are caused by the traditional “generalized” radiotherapy, which is “high but not low”, which not only does not help the local control rate of tumor, but also easily causes damage to normal organs. Now, with the continuous development of computer technology and imaging technology, the emergence of three-dimensional intensity-modulated conformal radiotherapy (IMRT) has truly realized the effect of “precise guidance”. According to the shape and size of the tumor, the dose distribution in the radiation field of each aspect is adjusted, so that the high-dose area in the three-dimensional direction exactly matches the shape of the target area, while minimizing the amount of surrounding normal tissue exposure. At present, our department has the world’s most advanced tumor radiotherapy equipment – TOMO radiation therapy system, as the representative of 3D image guided rotational intensity adjustment, its biggest advantage is “high conformal, high dose, low damage”. Even if the tissues and organs in close proximity are 1 -50px, it can produce a customized conformal dose distribution, while the dose to the surrounding normal tissues is steeply reduced.