Parents need to ask: Is this CT scan necessary?

I know a surgeon who, when consulted about a child with appendicitis, will insist that a CT scan of the abdomen be performed before he will see the patient. It doesn’t matter that the history and physical exam fit the diagnosis perfectly. It doesn’t matter that the child has already undergone an ultrasound of the appendix that shows it is dilated and inflamed. It doesn’t matter that the radiologist has tried to institute a protocol so that children have ultrasounds first and, only if that study is equivocal, will they have a CT scan.

Five to nine million children a year in this country undergo CT scans and it is estimated that up to a third of these are unnecessary or could be replaced by safer tests. But with last week’s news about the increased risk of childhood cancers after CT scans, they are going to become increasingly difficult to justify unless there is a clear medical benefit.

According to a new study published in the Lancet, multiple CT scans of the head tripled the risk of brain cancer and raised the incidence of leukemia in children under the age of 15. While the study did not investigate the increased cancer risk from abdominal CT scans, a CT of the abdomen delivers up to four to five times the radiation as a CT of the head, depending the technique used.

Radiation exposure in childhood is of particular concern for three reasons. First, cancer risk increases with the cumulative dose of radiation. Radiation exposure in the body accumulates over the lifespan of an individual. It does not wear off or go away. Second, tissues that have rapidly dividing cells, i.e. the growing organs of children, are more susceptible to radiation injury. Third, children may receive a higher radiation dose than necessary if CT settings are not adjusted for their smaller size.

In recognition of these facts the FDA issued a directive last month to companies that manufacture CT scanners to ensure that new imaging devices intended for use in the pediatric population be proven safe and come equipped with settings and instructions that minimize radiation hazards for children. The FDA is also advising parents to question whether x-rays are absolutely necessary and whether there are alternatives to diagnosis that don’t utilize radiation such as an ultrasound or MRI.

The American College of Radiology responded to the Lancet study acknowledging that pediatric CT scans can save lives but also advising parents to keep a record of their child’s x-ray history. Parents were urged to ask whether there are non-radiation alternatives to a recommended CT scan and whether the child will receive a “kid-size” dose of radiation.

A CT might render a quick, more definitive answer to the question of whether appendicitis is present but at what cost? Unnecessary CTs are already costly to the healthcare bottom line, but now there is another cost to contend with—the increased risk of cancer induced over a lifetime of radiation.

Parents are on the front line of this now clearly-recognized peril and they need to ask the question. Is this CT scan really necessary? Sometimes the answer will be a resounding “yes,” as in the case of head trauma or in a child with atypical abdominal pain or possible complications of appendicitis. But many times there will be a safer alternative and it is worth the effort to find out.

Catherine Musemeche is a pediatric surgeon. She can be reached on Twitter @DrKateM.

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