A computerized tomography (CT) scan is an invaluable diagnostic tool that can provide detailed images of internal structures. However, that information comes at a price: radiation exposure. The use of the technology has increased greatly during the past two decades has increased among all age groups, including children. Radiation exposure carries a risk of promoting cancerous growths. This risk is more worrisome for children because their organs are still developing and, compared to seniors undergoing a CT scan, they have many more years for a cancer to develop. A new study attempted to evaluate that risk. The results were published on June 10 in the journal JAMA Pediatrics.
The researchers attempted to quantify trends in the use of CT in pediatrics and the associated radiation exposure and cancer risk in seven US health care systems. From 1996 through 2019, the use of CT was evaluated for children younger than 15 years of age; the study comprised 4,857,736 child-years of observation. Radiation doses were calculated for 744 CT scans performed between 2001 and 2011. The main outcome measures of the study were rates of CT use, organ doses, and projected lifetime risks of cancer.
The authors noted that from 1996 through 2005 the use of CT doubled for children younger than five years of age and tripled for children five to 14 years of age; it remained stable from 2006 through 2007, and then began to decline. Effective doses varied from 0.03 to 69.2 mSv per scan. An effective dose of 20 mSv or higher was delivered by 14% to 25% of abdomen/pelvis scans, 6% to 14% of spine scans, and 3% to 8% of chest scans. Projected lifetime attributable risks of solid cancer were higher for younger patients and girls than for older patients and boys, and they 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. For girls, a radiation-induced solid cancer is projected to result from every 300 to 390 abdomen/pelvis scans, 330 to 480 chest scans, and 270 to 800 spine scans, depending on age. The risk of leukemia was highest from head scans for children younger than five years of age at a rate of 1.9 cases per 10,000 CT scans. Nationally, 4 million pediatric CT scans of the head, abdomen/pelvis, chest, or spine performed each year are projected to cause 4,870 future cancers. Reducing the highest 25% of doses to the median might prevent 43% of these cancers.
The researchers concluded that 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. Dose-reduction strategies targeted to the highest quartile of doses could dramatically reduce the number of radiation-induced cancers.
Take home message:
If a CT scan is recommended for your child, discuss the necessity of it and alternatives with a healthcare professional. As anything in life, risks versus benefits must be evaluated. Also ask if a low-dose CT scan is available. The lowered radiation of these scans reduces the risk. A study of low-dose CT scans conducted by Korean researchers at Seoul National University Bundang Hospital was published on April 26, 2012 in The New England Journal of Medicine.
To assess this problem, Korean researchers at Seoul National University Bundang Hospital evaluated the diagnostic accuracy of a low-dose CT scan versus a standard-dose CT scan in young adults with suspected appendicitis. Their findings were published in the April 26 issue of The New England Journal of Medicine. Appendicitis is one of the most common causes of emergency abdominal surgery in the United States. Prior to surgery, a CT scan is often done. The authors concluded that a low-dose CT scan was not inferior to a standard-dose CT scan in regard to false negative rates among young adults with suspected appendicitis.