CT scans are truly miracles of modern medicine. They enable us to more efficiently and effectively work up complex problems. By letting us look deep into the human body and see things not well seen with regular x-rays, ultrasound, or even MRIs, they expedite our efforts to quickly clarify confusing symptoms and make accurate diagnoses. CT scans can save lives, by showing that a patient with a headache actually has a cerebral hemorrhage, or by showing that the patient with abdominal pain has a brewing surgical emergency.
But CT scans also carry a cost. And I’m not just talking about money. CT scans involve significant radiation exposure, with a typical CT scan delivering as much radiation into a person as 200 chest x-rays. We all know radiation exposure creates a potential risk of cancer. While this risk applies to everyone, children are at higher risk. Their organs are growing and developing more rapidly than in adults. Their body mass is smaller, so equivalent doses of radiation can have more impact.
A recently published study in JAMA Pediatrics confirms the potential risk for cancer from CT scans in children, and should give all clinicians pause. The study looked at 11,000,000 children in Australia who received at least one CT scan between 1985 and 2005. The risk of any form of cancer was 24% higher at 9.5 years for children who had had at least one CT scan, compared to children who had never had one. The more scans a child had, the higher the risk of cancer. Children who had a CT scan when under age 5 had the highest risk of developing a subsequent cancer.
A second study in the same journal shows that CT ordering for pediatric patients is rising. The authors estimate that pediatric CT scans in the year 2011 in the U.S. will lead to 4,870 extra cancers.
Obviously there are times when children need to have a CT scan. These two recent articles do not reach the conclusion that CTs should never be done in kids. But it is important, when contemplating ordering this study in a child, to make sure it is really necessary, and that the information being sought cannot be obtained through some other modality.
Richard Fleming, MD