Intensification of pediatric tumors Radiotherapy for pediatric tumors is relevant to the child, the tumor, and healthy tissue. For example, the five-year overall survival rate for intracranial spermatogenic tumors in children can approach 100%. The greatest concerns in pediatric radiotherapy are late complications and the development of second tumors. Compared to adults, pediatric tumors require relatively low doses of radiation therapy, but require relatively large volumes of radiation therapy, especially for whole cranial and spinal cord radiation therapy for medulloblastoma. At the same time, in order to maintain the symmetry of bone development, the irradiation field is expanded so that the dose is uniform throughout the spinal bone. Therefore, the indications for radiotherapy of pediatric tumors must take into account healthy tissue that is still growing and highly radiosensitive, and sometimes tumors with a genetic background are particularly sensitive to radiation therapy, such as tumors with Fraumeni syndrome and neurofibromatosis. Similarly, each case of pediatric radiation therapy must be multidisciplinary and utilize the best techniques so that the most precise target area can be obtained and the maximum amount of healthy tissue can be protected. Intensity-modulated radiation therapy allows for optimal distribution of the radiation dose while avoiding organs at risk, resulting in a uniform dose to the target area. In adults, intensity modulation was introduced in 1990. This technique allows the dose to be distributed according to the shape of the tumor and maximizes the protection of healthy tissue and limits toxicity, while increasing the dose. For tumors that are associated with a total dose (e.g., head and neck tumors), increasing the irradiation dose to the tumor means that the local control rate can be improved. The use of intensity modulation in children began in 2002. There are no randomized alternative radiotherapy techniques in children that are comparable to the intensity modulation technique, and the only available data are based on the feasibility and clinical benefit of utilizing the intensity modulation technique as demonstrated by historical or prospective comparative study groups. This technique can lead to high-quality radiotherapy for pediatric tumors, especially when the target area is complex in shape (e.g., whole ventricle radiotherapy for malignant germ cell tumors of the brain or large area irradiation for nephroblastoma) or close to vital organs at risk (e.g., radiotherapy for Ewing’s tumor of the spine). The use of intensity modulation in children may reduce near- or long-term toxic effects while increasing the target dose to the tumor. Priorities should be established before achieving an intensity-modulated radiotherapy program: local tumor control, growth and development, and second tumor generation risk ……