Medical radiation is the largest source of man-made radiation exposure in the U.S. The average background radiation exposure (from the sun, earth, etc.) is 3-5 mSV per year. While traditional X-rays emit minimal radiation, CT scans expose patients to 3-5 mSV, equivalent to a year of background radiation. CT scans provide approximately 75% of the U.S. population’s man-made radiation exposure. Other studies such as upper GI, VCUG (voiding cystourethrogram), PET scans and bone scans emit similar doses to CT. It has been estimated that up to 1/3 of all radiology exams are unnecessary.
It is well known that high dose radiation (>100 mSV) exposure is associated with an increased risk of cancer, but it is unknown how low-to-medium dose radiation affects that risk. Children are at greater risk, because the cancer risk increases with decreasing age, and the absorbed dose is size-dependent – the smaller the patient, the larger the absorbed dose.
Radiation from diagnostic imaging procedures may cause a very small increase in the risk of cancer. . It is estimated that one CT scan may cause a 1 in 2000 risk of developing a fatal cancer. However, many lives are saved by appropriate use of radiology imaging, so the benefits far outweigh the risk of radiation exposure.
Physicians are aware of the risks of radiation exposure, but parents should not be afraid to discuss diagnostic imaging options. They should discuss imaging procedures that do not emit radiation (MRI, ultrasound), or ways to limit the exposure: avoiding unnecessary radiology exams, or optimized pediatric CT protocols to decrease radiation exposure. Pediatric hospitals optimize their CT protocols to limit exposure to children, so may be safer than other radiology clinics. If your child requires a CT scan or any form of imaging requiring radiation, please make sure to work with a pediatric radiologist at a facility that specializes in pediatric medicine. The doctor’s primary focus and expertise should be in safe dosing for children. Don’t be afraid to ask questions.