How Boston Children’s keeps radiation exposure as low as possible

Computed tomography (CT) scans may place children at an increased risk of cancer, according to two recently released studies published in Journal of the American Medical Association (JAMA) and the British Medical Journal (BMJ).  

Despite the highly publicized radiation risks associated with high-dose CT scans, Boston Children’s Hospital has been at the forefront of a movement to reduce the levels of radiation exposure to young patients for years.

CT scans produce high-quality images of inside patient’s bodies and are especially helpful in diagnosing certain illness or injury, like severe brain trauma, appendicitis or problems inside a person’s lungs. To produce their images, CT scanners use highly focused, x-ray beams. When child-sized doses are used, the patient’s level of exposure to radiation is relatively low. Although the risks from low levels of ionizing radiation are not well understood, we assume that even a small exposure to ionizing radiation could potentially lead to an increased risk of cancer and do everything we can to use the minimum amount of radiation necessary to obtain appropriate medical images.

Michael Callahan, MD

Children are especially susceptible to this exposure, because their developing tissues are more sensitive to the effects of radiation than are the mature tissues in adults. Children also generally have a longer life expectancy than adults, and as a result, may have a greater chance of developing a radiation-induced cancer during their lifetime.

Because they work almost exclusively with young patients, the physicians and staff at Boston Children’s Department of Radiology are well aware of these risks and committed to reducing them.

Michael Callahan, MD, Boston Children’s director of CT imaging, is a national member of the Alliance For Radiation Safety in Pediatric Imaging’s steering committee, and is actively involved in the Image Gently campaign, an international organization dedicated to educating medical professionals and parents about the potential risks associated with CT scans in children. Together with a team of radiologic technologists and radiation physicists, Callahan is leading an effort within Boston Children’s to reduce the amount of radiation used for CT scans and to reduce the overall number of CT scans in children.

Here are just a few of the methods Boston Children’s uses to achieve this goal:

Advocate for alternatives when appropriate. In some clinical situations, ultrasounds or MRI examinations—imaging procedures that do not utilize ionizing radiation—can be as accurate as CT scans and are used whenever possible.

“We don’t yet know the true risks of ionizing radiation from CT, but we do know children’s bodies are more radiation sensitive than adults,” Callahan says. “And as a result, every time we are asked to conduct an imaging study with ionizing radiation we should consider using imaging modalities that do not require the use of ionizing radiation, such as ultrasound or MRI.”

Ultrasound uses sound waves to image the body and can answer some of the same questions as CT. Ultrasound also doesn’t require the child to stay completely still during the exam, so it’s often the study of choice in very young children.

Because MRIs require patients to remain very still for a prolonged period of time (sometimes more than an hour), young patients or older children who have a problem staying still may require sedation or anesthesia to have an MRI. In an attempt to reduce the need for sedation, our staff is specifically trained to work with children. We have many techniques—games, specially designed video goggles and music—that keep many of our younger patients entertained—and motionless—for their MRI. Thanks to these techniques, children as young as 4 years-old are often able to sit through the MRI without the need for sedation or anesthesia.

In cases of non-severe head injury, in 2011, Boston Children’s researcher Lise Nigrovic, MD, MPH, released a study in the journal Pediatrics stating that when emergency department clinicians carefully observe patients at intermediate risk of head trauma for a few hours following injury, they should be able to accurately determine the severity of the injury without a CT scan. She also found that prolonged observation did not compromise patient safety in any way.

Boston Children’s emergency physician Lois K. Lee, MD, MPH, is part of Pediatric Emergency Care Applied Research Network (PECARN), a nationwide consortium of emergency medicine doctors and radiologists that is developing guidelines for when children with head or abdominal trauma should have a CT scan. Their head guidelines could cut the number of children who receive a CT scan for head injury by 25 percent. “Avoiding CT scans in those at a low risk for [head] and intra-abdominal injury will be an important part of reducing CT use in children and, consequently, their future risk of lethal malignancies,” she says.

Use “child-sized” CT protocols. When a CT scan is the best option for obtaining a clear diagnosis, radiologists at Boston Children’s use the smallest radiation dose possible to produce images of diagnostic quality. In the medical field at large not all CT scans are performed with pediatric settings, however, CT imaging at Boston Children’s is adjusted for each patient’s individual size and reason for exam, ensuring the greatest safety by using the lowest necessary radiation exposure.

“The medical physics staff at Boston Children’s is constantly thinking of ways to make our equipment work best for children,” says Kevin Buckley, MSc, the hospital’s director of radiology physics and engineering. “And our technologists and radiologists are highly experienced in treating children.”

Constantly re-evaluate. Commitment to safety means not resting on your laurels. “We constantly review our protocols, equipment and procedures, and we make changes to make CT as safe as we can based on the best science we have available,” says Richard Cappock, RT, Boston Children’s CT Operations Manager.

CT scan

Take a unique, organ system-focused approach. Members of the Radiology Department team subspecialize in the disease or organ system being imaged. Working together with your child’s other doctors, our expert radiologists are able to determine what imaging test is best and avoid unnecessary radiation exposure whenever possible. Boston Children’s is the first pediatric hospital in the country to take this approach. And because our radiologists are expert at reading pediatric exams, they can properly diagnose with a lower resolution image, allowing them to use even less radiation to achieve an accurate diagnosis.

“When used properly, CT can be a life-saving technology,” Callahan explains. “If we need to perform a CT, we tailor the patient’s dose based upon the clinical question and keep our CT doses as low as reasonably possible while still answering the question for our clinical colleagues.”

It’s possible that these new studies may alert others in the medical field about the need for caution when using CT scans on children. Increased awareness among doctors is important, but parents still need to play an active role in advocating for their child’s safety. If your child requires imaging testing that you aren’t familiar with, ask the following questions:

  • What is the name of the test you are suggesting for my child?
  • Does the test involve ionizing radiation?
  • How will the test improve my child’s care?
  • Are there any non-ionizing radiation tests that could be safely used?
  • Will my child receive a “kid-sized” dose of radiation?
  • Is this facility accredited by the American College of Radiology?
  • Is the radiologist reading the results a board certified pediatric radiologist or neuroradiologist with expertise in the condition being studied?

“You should always feel comfortable talking to your pediatrician or radiologist if you have questions about radiation safety and radiation dosing,” Callahan says.

To learn more about the value of choosing Boston Children’s for your pediatric imaging needs, please visit the following sites:


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