Children are commonly exposed to ionizing radiation from medical diagnostic imaging procedures
Research Activities, November 2011
Use of medical diagnostic imaging is not uncommon among children under 18 years old. The highest rates are in children older than 10, with frequent use in infants younger than 2 years as well, reveals a new study. This is worrisome, note the researchers. That's because infants and children exposed to ionizing radiation are at higher risk of developing cancers and other problems than adults, because their longer expected lifespan means a longer time for adverse effects to emerge, and their rapidly developing tissues are more sensitive to radiation damage. The researchers found that 42.5 percent of the 355,088 children studied underwent 436,711 imaging procedures during the 3-year study period. A fourth of the children underwent two or more such procedures, while 16 percent underwent 3 or more procedures.
Children older than 10 years had the highest rate of all imaging procedures involving ionizing radiation (506-512 per 1,000 person-years), with high rates of use in infants younger than 2 years as well. Plain x-rays accounted for 84.7 percent of imaging procedures performed. However, computed tomographic (CT) scans, which are linked to substantially higher doses of radiation, were commonly used—accounting for 11.9 percent of all imaging procedures during the study period. Overall, 7.9 percent of children received at least one CT scan and 3.5 percent received two or more. Children under 2 years old accounted for 1,675 of the patients undergoing CT imaging for 27 CT scans per 1,000 person-years. Nearly 40 percent of children received at least 1 plain x-ray, with children age 10 years and above having the highest rates of use (395-441 x-rays per 1,000 person-years).
While the rate of plain x-rays was highest for the chest (68 procedures per 1,000 person-years), the CT imaging rate was highest for the head (15 procedures per 1,000 person-years). The findings were based on inpatient and outpatient claims data for 355,088 children enrolled in a large health care plan from the beginning of 2005 through the end of 2007. The study was funded in part by the Agency for Healthcare Research and Quality (HS18781). More details are in "Use of medical imaging procedures with ionizing radiation in children. A population-based study," by Adam L. Dorfman, M.D., Reza Fazel, M.D., M.Sc. Andrew J. Einstein, M.D., Ph.D., and others in the May 2011 Archives of Pediatrics and Adolescent Medicine 165(5), pp. 458-464.