US Physicians Making CT Safer for Children

Radiologists are urging parents that they should carefully assess the benefits and risks.

More than four million pediatric CT scans were performed in the United States in 2012. The experience can leave a parent a little worried, because the radiation from a CT scan may increase the risk of cancer, especially in children. However, this may be changing for the better, especially for children, who are even more vulnerable to radiation-induced cancer than adults.

In data gathered by the American College of Radiology’s (Reston, VA, USA) Dose Index Registry, which tracks and categorizes the radiation given by CT scanners in US hospitals, Yale-New Haven Children’s Hospital (YNHCH; New Haven, CT, USA) recorded the lowest doses of any academic hospital in the country in many age groups and types of pediatric radiation.

“The numbers are very impressive,” said Rob Goodman, MD, chief of pediatric diagnostic imaging at Yale. “We’ve more than halved the number of CT scans performed on children despite more than doubling the number of scanners in the hospital.” In 2003, Yale-New Haven had three CT scanners and performed 4,844 CT scans on children. In 2012, with seven scanners, the hospital performed 2,344.

The low numbers are partly due to a greater awareness among physicians. Pediatric emergency specialist Lei Chen, MD, who has used the test to make urgent diagnoses of such problems as suspected appendicitis or head injury, said, “We have really started thinking critically about the risks and benefits of CT scans. We often elect alternative strategies: either watchful waiting in cases of suspected head trauma or ultrasound and MRI.”

CT scanning save countless lives, and prevent many misdiagnoses and unnecessary surgeries. As a result, its use has surged in the last 20 years. But its diagnostic power can expose a patient to 100 to 500 times the amount of radiation they would get in an X-ray, increasing the patient’s risk for cancer. Children’s smaller, rapidly changing bodies are more susceptible to ionizing radiation and therefor to the risk of cancer from it.

Rob Goodman, MD, began altering the use of CT scans for pediatric patients in 2003. In January 2008, the Alliance for Radiation Safety in Pediatric Imaging, representing more than 70 medical organizations, launched the Image Gently campaign to educate doctors and the public about cumulative radiation exposure. Manufacturers began designing scanners that automatically adjusted the dose based on the patient’s age and weight, as well as the sensitivity of the area to be scanned.

Dr. Goodman became concerned about CT scan radiation even earlier, when he came to Yale from Oxford in 2003, and realized that Americans were getting three times more medical radiation than Europeans. He began conducting grand rounds for pediatricians on slashing radiation doses, and urged them to consider options to CT scans such as ultrasound. He worked with YNHCH’s medical physicists to tweak the CT scanners to give children the least possible dose while still making images acceptable to the radiologists for diagnosis.

Dr. Goodman expects Yale’s numbers to drop further as new software improves the grainy images yielded by low-dose CT scans, and as magnetic resonance imaging (MRI), which produces no radiation, replaces CT scans for making some diagnoses.

Dr. Goodman explains the procedure to a family. Parents need to weigh the benefits and risks of CT scans. Not all imaging centers have changed their approach. A study published in JAMA Pediatrics in 2013 reported that of the estimated four million CT scans given yearly to US children under age 15, one-third are unnecessary and may lead to 5,000 cases of cancer.

Still, doctors say that in some cases a CT case is the best test. “If we can get the necessary information from a plain X-ray or an MRI, we forego the CT scan,” said Yale pediatric orthopedic surgeon Cordelia Carter, MD. However, for certain fracture patterns, such as a common ankle fracture called a triplane fracture, a CT scan provides the amount of detail a surgeon requires, she reported. “MRI is better for soft tissue, CT is best to evaluate the bone and joint surfaces. Sometimes an X-ray doesn’t show us enough.”

Nevertheless, Dr. Carter added, “From an orthopedics perspective, we are very aware of the increased radiation associated with CT scans, and we do whatever we can to minimize the patient’s exposure.” If the patient has a triplane fracture, Dr. Carter asks the technologist to image only the area she needs to see for surgical planning, and not areas outside of that field.

Similar to any test or treatment, parents must weigh the benefits and risks, Dr. Goodman noted. “If the suspicion is high that your kid may have a lesion in the lung, don’t worry about the radiation, just do what’s best for the patient.”

Related Links:
American College of Radiology’s Dose Index Registry
Yale-New Haven Children’s Hospital