Key points: (1) The younger the child, the higher the radiation dose received and the greater the risk of cancer (2) Headaches in children do not always require a CT cranial examination CT is the standard clinical examination for many diseases. According to statistics, more than 4 million children in the United States underwent CT exams in 2011. The average radiation dose for a CT examination is 2.34 mSv, which is equivalent to approximately 200 standard chest radiographs. Recent studies have evaluated the risk of malignancy in children after CT exams and the use of cranial CT exams in children with headaches. The researchers analyzed the association between CT exams and malignancy in nearly 11 million Australian children aged 0-19 years, born between 1985 and 2005. The results showed that 6 percent of the children had at least one CT examination. Cancer was diagnosed in 60,674 children 1 year or more after radiation exposure. On average, 9.5 years after CT radiation exposure, the CT group had a 24% increase in cancer incidence compared to the no CT group; and for each additional CT exam, the cancer incidence increased by 0.16. The risk of cancer was similar at 5 and 10 years after exposure to CT radiation. The average amount of radiation received from a single CT scan of all organs was 4.5 mSv. The risk of developing malignant tumors of the brain was highest in children of all ages, less than 5 years old. Another study analyzed the risk of radiation exposure and malignancies in children younger than 15 years of age after CT examinations in seven different types of health centers in the United States. The results showed that the number of CT exams doubled between 1996 and 2005, remained stable between 2006 and 2007, and decreased by 14% in 2010;. The highest radiation doses were received from CT scans of the abdomen and pelvis. in children under 5 years of age, the highest radiation doses were received from CT scans of the bone marrow in the head. The risk of developing solid tumors after abdominal or pelvic CT scans was greater in girls than in boys, at 26 to 34 cases of cancer per 10,000 CT scans. The risk of developing leukemia was highest after CT scans of the head in children younger than 10 years of age. The authors estimate that 4 million children in the United States received CT exams in 2011, resulting in 4,870 cases of malignancy in the future. Reducing the highest radiation dose CT exams to a moderate dose might prevent 43%; of cancers. Other authors investigated the use of cranial CT scans in children and found that the use of cranial CT exams in emergency departments and pediatrics to evaluate children for headaches remains common. The American Academy of Pediatrics does not currently recommend the use of cranial CT scans to evaluate children for headache, but the investigators found that 25% of the 15,836 children aged 3-17 years who complained of more than 2 headaches between 2007 and 2008; still had a cranial CT exam, but making a preliminary diagnosis was not influenced by whether or not a CT exam was performed, nor was the diagnosis of most patients before or after the CT examinations changed. Neurologists prescribed the fewest requests for cranial CT and family physicians the most. 2/3 of children had not been systematically evaluated for headache before having a cranial CT in the emergency department. Comments: (1) A considerable number of unnecessary CT examinations and radiation exposures in children can be effectively reduced by limiting the number of cranial CT examinations performed for headache. (2) CT examinations in children must balance the advantages and disadvantages, should be limited to cases where they are absolutely necessary, and a pediatric radiation dose pattern must be used during the examination. (3) After children have received a significant dose of radiation exposure, signs of malignancy should be routinely and carefully looked for in subsequent health care, especially in children who have undergone multiple CT examinations.