by Gerry Le
Computed tomography (CT) scans allow medical professionals to look inside a patient's body without ever having to make a physical incision. However, the radiation that the patient is exposed to during these scans is potentially harmful, especially for pediatric patients.
Radiation is a concern because exposure has a theoretical risk of causing cancer during a patient's lifetime. According to research, there is a risk that one child in every 1,000 who undergoes a CT scan will develop a fatal cancer during the course of his or her lifetime. As the dosage increases, the cancer risk also will increase.
MUSC Children's Hospital is taking measures to reduce radiation exposure in its patients through multiple strategies, one of which is the development of clinical guidelines for trauma patients and patients with suspected appendicitis by incorporating early surgical consults prior to the performance of CT scans.
Christian Streck, M.D., assistant professor of pediatric surgery, said children are more prone to cancer through radiation because of three factors: 1) a young child's cells are still rapidly dividing; therefore, their tissues are more sensitive to radiation, 2) a child has a longer lifespan than an adult and a longer time to manifest the potentially harmful effects of radiation, and 3) the radiation dose and its effects are cumulative during the child's lifetime.
In the past six years, the overall amount of CT scans has risen significantly, particularly in emergency medicine, according to Streck. "In the past, doctors used medical history and physical exams to evaluate a patient. Now, it just seems easier for a doctor to order a scan before even seeing a patient," he said.
Nationally, two of the most common diagnoses for which CT scans are ordered include suspected appendicitis and trauma. Streck said many asymptomatic trauma patients undergo "pan CT" of the head, neck, chest, abdomen and pelvis evaluating for injury. Although CT scans are helpful in carefully selected children with specific clinical signs of pathology, the "old fashioned" physical examination is enough for a surgeon to decide if intervention is needed in most cases.
According to Streck, MUSC sees about 100 appendicitis cases and 300 trauma cases each year.
"These are the two cases where people overuse CT scans in children," Streck said. "For most patients, CT should be the last option, and a hands-on evaluation should be the first step to diagnosis." By implementing a clinical pathway with earlier surgical evaluation, MUSC has reduced the amount of CT scans in appendicitis cases by about 80 percent and in pediatric traumas by almost 50 percent in the past several years, said Streck.
Jeanne G. Hill, M.D., professor of radiology and pediatrics, said there are multiple ways to minimize a child's exposure to radiation. First and foremost, any imaging, particularly if it requires radiation, should be indicated by the clinical situation.
"The physician needs to weigh the risks and benefits of CT scans in children," Hill said. If, in fact, the CT is indicated, the technical parameters are tailored to the size and weight of the child, the examination is limited to the area of clinical interest and repeat scanning is avoided. In consultation with the radiologist, alternative imaging modalities that do not utilize radiation may provide adequate information. In the case of appendicitis, MUSC uses ultrasounds as the primary imaging modality. CT scans are reserved for problematic cases.
Both Streck and Hill believe that an ultrasound is a better alternative to CT scans in pediatric patients because of the lack of body fat and smaller size of children. However, according to Hill, CT scans in many institutions are used rather than ultrasounds because ultrasounds are operator dependent and many sonographers do not feel comfortable scanning children.
Another alternative to CT scans is the MRI, which does not utilize ionizing radiation. MRI scans are significantly more time consuming, and they require the patient to stay very still for longer periods of time, usually resulting in children being sedated. Streck and Hill agree that if MRI scans were faster, they would be a much better alternative.
Even though there is a higher cancer risk with CT scans, Streck and Hill stress that the fear of radiation should not negatively influence appropriate medical treatment for a child. Benefits of an appropriately indicated CT scan far outweigh the potential risks, according to Hill.
"MUSC Children's Hospital, through the implementation of clinical guidelines and research, will continue to develop strategies to minimize the risk of radiation exposure associated with CT scans," Hill said.