“Ionizing radiation comes to us from various sources, and a variety of human tissues are sensitive to it,” said Michelle S. Caird, MD, speaking at the 2014 annual meeting of the Pediatric Orthopaedic Society of North America. “In recent years, the use of radioimplant and imaging studies has increased in the United States, both among adults and, alarmingly, in children—especially with computed tomography (CT) scans and an increased use of fluoroscopy in the operating room.”
According to Dr. Caird, estimating radiation doses for children is a complex process that, among other factors, takes into account the size of the patient, the thickness of the patient in cross-section in the plane of the beam, and the composition of tissue in the energy beam.
Dr. Caird explained that most of the published literature on radiation in orthopaedics is based on scoliosis monitoring.
“Research has demonstrated that a posterior-anterior radiograph provides a lower radiation dose to breast and thyroid tissue than an anterior-posterior radiograph,” she said. “Digital radiographs offer arguably less radiation exposure. This provides us with an opportunity to reevaluate our monitoring strategies, especially for early onset scoliosis patients, who will continue to be monitored over a long period.”
Dr. Caird pointed out that vast changes in practice and protocols for CT scans have occurred in recent years, especially in the area of pediatric cervical spine trauma. Such changes have improved image quality, but those same improvements may lure physicians into greater reliance on scanning.
“The imaging has become sharper and the scans are becoming faster. But sometimes that means increased radiation, and we again have to remember to take into account those early onset scoliosis patients,” she said.
A fluoroscopic “crutch”?
In addition to scans, another factor orthopaedists can control is the use of intraoperative fluoroscopy. Dr. Caird explained that use of fluoroscopy can easily turn into a crutch for the physician and argued that surgeons should consider alternatives that present less radiation exposure to the patient.
“There are now devices to place distal interlocks without using radiation,” she said. “For slipped capital femoral epiphysis pinning, we can control the table and the positioning of the patient, which can vastly affect the amount of radiation that the patient receives. Because teaching pedicle screw insertion can be harrowing, we need to evaluate how we teach this skill.
“Fluoroscopy is still needed for localization,” she continued, “but we can control the number of spins we put the patient through.”
Dr. Caird also addressed the issue of intraoperative CT navigation, calling it “a wonderful tool.” But she pointed out that the process results in significantly higher radiation doses to obese patients.
Reducing the staff hit
Radiation concerns exist for healthcare providers as well, noted Dr. Caird.
“Will respect to CT navigation, the doses for surgeons are much lower than those for patients; we can hide behind our lead screens,” she said. “Surgeons and staff wear dosimeters to monitor exposure. Time, distance, and shielding are our tenets.”
However, she noted that surgeons and staff receive most of their radiation from scatter, often directly to the hands, and through procedures using C-arms and mini C-arms.
“The dose in a mini C-arm has actually been creeping up over the years as the images get sharper, and we should be aware of such things,” she explained.
“We can shield ourselves,” she continued. “Some new studies demonstrate that improved education programs for trainees and surgeons can reduce the fluoro time. As leaders of the staff, we can decrease the time of shots; we can position the patient. We also need to remember to regularly monitor ourselves and to watch our own dose reports.”
Keep the pressure on
According to Dr. Caird, the push to develop improved CT scanners that produce less radiation is ongoing. For imaging pediatric patients using existing scanners, she recommends turning down the current and adjusting the tube potential to minimize exposure.
She also urged her colleagues to consider ongoing developments in the field that may reduce radiation exposure.
“There have been great developments in alternative imaging,” she said. “As surgeons, we should keep the pressure on to encourage further progress in this area. There are proposals to monitor lifetime dosing for pediatric patients. It’s critical to use radiology technicians who are familiar with scanning children. We can limit the spins in CT navigation. We need to push our electronic health records systems to offer us greater flexibility in ordering tests.
“Finally, we can take care when we order scans,” she continued. “We should ask ourselves, ‘Will the next film or study that exposes this patient to radiation change my treatment plan? Is there another test with lower radiation—magnetic resonance or ultrasound—that could be used instead?’ As a society, we should develop evidence-based guidelines for exposing patients to radiation.”
Disclosure information: Dr. Caird—Orthopaedic Research and Education Foundation, Pediatric Orthopaedic Society of North America.
Peter Pollack is the electronic content specialist for AAOS Now. He can be reached at firstname.lastname@example.org
The Image Gently Alliance
The mission of the Alliance for Radiation Safety in Pediatric Imaging (the Image Gently Alliance) is to improve the safety and effectiveness of the imaging care of children worldwide, through increased awareness, education, and advocacy regarding appropriate examination and radiation dose when imaging children. The ultimate goal of the Alliance is to change practice locally to improve the health and safety of the child.
Learn more at www.imagegently.org