 Around 175,000 children are diagnosed with cancer every year. With early diagnosis and treatment, up to 80% of them can be cured. But special care is essential for the safe treatment of children with cancer. Many of them will need radiotherapy to kill the cancer cells. Children are not adults, they are small. We also know that their sensitivity to radiation is greater. Pediatric oncology helps to identify and fight the disease. Childhood cancers are different from adult cancers. They often require a longer and more intense treatment. The IAEA supports member states like Mexico and Uruguay by training staff in the comprehensive care of children with cancer. The capacity of the organism is very important. It gives us tools to reach the child in a friendly and empathetic way. Medical treatment can be a major source of anxiety and stress for children. But explaining the procedure using toys can make them feel safe. In this way, children can know what will happen and cooperate with us with greater ease. They no longer have anguish. Nuclear medicine and radiotherapy play a vital role in the lives of many children with cancer around the world.