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Pediatric radiation exposure from computed tomography scans linked to cancer risk

According to a study of seven U.S. healthcare systems, the use of computed tomography ( CT ) scans of the head, abdomen / pelvis, chest or spine, in children younger than age 14 more than doubled from 1996 to 2005, and this associated radiation is projected to potentially increase the risk of radiation-induced cancer in these children in the future.

The use of CT in pediatrics has increased over the last two decades. The ionizing radiation doses delivered by the tests are higher than convention radiography and are in ranges that have been linked to an increased risk of cancer. Children are more sensitive to radiation-induced carcinogenesis and have many years of life left for cancer to develop.

The increased use of CT in pediatrics, combined with the wide variability in radiation doses, has resulted in many children receiving a high-dose examination.

Diana L. Miglioretti, of the Group Health Research Institute and University of California, Davis, and colleagues quantified trends in the use of CT in pediatrics plus the associated radiation exposure and estimated potential cancer risk using data from seven U.S. health care systems.

The authors have noted the use of CT doubled for children younger than 5 years old and tripled for children 5 to 14 years of age between 1996 and 2005 before remaining stable between 2006 and 2007 and then beginning to decline.

The projected lifetime attributable risks of solid cancer were higher for younger patients and girls than for older patients and boy. The risks were also higher for patients who underwent CT scans of the abdomen/pelvis or spine than for patients who underwent other types of CT scans.

The estimates also suggest that for girls, a radiation-induced solid cancer is projected to potentially result from every 300 to 390 abdomen / pelvis scans, 330 to 480 chest scans, and 270 to 800 spine scans, depending on age. The potential risk of leukemia was highest from head scans for children younger than 5 years of age at a rate of 1.9 cases per 10,000 CT scans.

The authors estimate that 4,870 future cancers could be caused by the 4 million pediatric CT scans performed each year. Based on their calculations, the authors also suggest that reducing the highest 25% of doses to the median may prevent 43% of these cancers.

More research is urgently needed to determine when CT in pediatrics can lead to improved health outcomes and whether other imaging methods ( or no imaging ) could be as effective. For now, it is important for both the referring physician and the radiologist to consider whether the risks of CT exceed the diagnostic value it provides over other tests, based on current evidence.

In a related editorial, Alan R. Schroeder, of the Santa Clara Valley Medical Center, San Jose, and Rita F. Redberg, editor of JAMA Internal Medicine and of the University of California, San Francisco, have written: minimizing radiation exposure by eliminating unnecessary scans and by using the minimal dose necessary to achieve a satisfactory image for necessary scans is a high priority. But we can still do more to decrease the use of unnecessary scans ( for which the benefit does not outweigh the risk ) and to decrease the level of radiation exposure from necessary scans. This will require a shift in our culture to become more tolerant of clinical diagnoses without confirmatory imaging, more accepting of watch and wait approaches and less accepting of the another test can't hurt mentality. Uncertainty can be unsettling, but it is a small price to pay for protecting ourselves and our children from thousands of preventable cancers. ( Xagena )

Source: JAMA Pediatrics, 2013