Article from: Fall-Winter 2017



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    By Pat McGrath

    Safety First

    How Pediatric CT Protocols Help Protect Kids for a Lifetime

    James R. Duncan, MD, PhD
    Left to Right: James R. Duncan, MD, PhD, Vice Chair for Quality and Safety at MIR, Madelyn Scheipeter and her mother, Monica, and MIR’s safety team coordinators, Mike Harrod and Bekah Phelan.  

    For many, saving small amounts of money here and there over time can make a significant difference in their financial future. According to James R. Duncan, MD, PhD, professor of radiology, the same is true with radiation exposure in children.

    “If we make decisions that reduce radiation, whether in the dose used to complete a CT scan, a fluoroscopic procedure or being creative in obtaining the information we need through other imaging modalities, then we are helping to establish a radiation budget that can reduce a child’s lifetime exposure,” he explains.

    Budgeting for pediatric exposure to radiation began in the 1980s, when computed tomography (CT) started coming into its own. CT gave radiologists the unique ability to produce cross-sectional images that provided detailed pictures of the body’s soft tissues. Today, CT imaging is a trusted, vital tool in helping clinicians diagnose disease and injury in people of all ages.

    From the start, Mallinckrodt Institute of Radiology (MIR) has been at the forefront of developing pediatric CT protocols. Now its pediatric radiology specialists have established what is proving to be an effective outreach program that ensures children receive the lowest possible dose of radiation while undergoing CT scans at hospitals throughout the BJC HealthCare System. At its core is the doctrine followed by all medical professionals who treat pediatric patients: Children are not simply small adults.

    Setting a Radiation Budget

    Duncan is among the leaders of this outreach effort. “National campaigns such as the Image Gently Alliance established in 2007 have raised awareness of the need to adjust radiation dose when imaging children,” he says. “More recently, The Joint Commission, an independent, not-for-profit organization that accredits and certifies health care organizations, has emphasized the importance of including patients’ radiation exposure in their medical records.”

    James R. Duncan, MD, PhD
    Above: James R. Duncan, MD, PhD, a professor of radiology, was appointed Vice Chair for Quality and Safety in 2015.

    At MIR over the past decade, the radiologists who specialize in pediatric imaging at St. Louis Children’s Hospital (SLCH) have made significant progress in reducing radiation exposure during CT imaging. A study published in 2015 in RadioGraphics reported a twofold reduction in CT radiation exposure in pediatric patients between 2007 and 2012. This was achieved by adhering to low-dose CT as a standard protocol. In addition, they cut CT use in children by approximately 50% over the five-year period by increasing the availability of magnetic resonance and ultrasound imaging, neither of which use radiation.

    “These are impressive improvements that have been championed by MIR’s pediatric radiology specialists,” says Duncan. “Unfortunately, statistics show that only about 20% of pediatric imaging occurs at pediatric specialty hospitals such as St. Louis Children’s. The other 80% are done at local community hospitals, where in a typical busy day their radiology department may perform scans on 20 adults, then one child, followed by another 20 adults. Pediatric protocols need to be followed for that one child, but that doesn’t always happen.”

    Change Was Needed

    The success of SLCH in reducing its patients’ radiation exposure, and the knowledge that the 11 other hospitals in the BJC Healthcare System may not be achieving the same results, spurred MIR to launch an outreach program designed to ensure compliance with pediatric CT protocols. The first step was to evaluate the current usage within BJC. The statistics were telling.

    “When Children’s Hospital was included in the evaluation, use of pediatric protocols stood at 60%. When Children’s Hospital was excluded, that dropped to 8%,” says Duncan. Clearly changes were needed. Fortunately, a BJC-wide Radiology Clinical Expert Council had been formed and that group selected pediatric CT protocols as one of its first improvement initiatives. A dose monitoring system was purchased and used to collect data from all CT scanners within the system.

    “This dose monitoring system captures the child’s date of birth, date of CT exam, exam name, protocol used for the study, identifiers for the CT scanner and hospital, as well as dose metrics such as dose length product and CT dose index,” explains Michael Harrod, quality and safety coordinator technologist at MIR. “This has proven to be a real advantage in our ability to track whether or not pediatric CT protocols are being used appropriately.”

    Marilyn J. Siegel, MD
    Above: Marilyn J. Siegel, MD, along with technologist Christi Lappe reviews a pediatric CT scan.

    To further improve support, Timothy Street, a clinical application specialist for BJC HealthCare, and Christi Lappe, charge technologist at St. Louis Children’s Hospital, began visiting individual BJC hospitals to educate radiology technologists about pediatric CT protocols and the dose monitoring system.

    “This was particularly important because Tim and Christi are technologists themselves, so they were able to effectively communicate to people with the same backgrounds and training,” says Bekah Phelan, MIR’s quality and safety nurse coordinator.

    With all elements in place, the Radiology Clinical Expert Council began tracking the use of pediatric CT protocols at BJC hospitals. Between March 2015 and January 2017, the hospitals improved from 8% to 85% compliance. (This excludes SLCH, which consistently complies with the pediatric protocols.) While the improvement is impressive, the goal is to reach 95% compliance in pediatric CT protocol use at the BJC hospitals.

    Moving the Dial Down

    MIR’s pediatric radiologists are experts at reading children’s CT imaging studies, even when very low doses of radiation are used. It’s a learned skill, and one not easily achieved by radiologists who mainly deal with adults.

    “The fact is, however, that even a 10% decrease in radiation dosage is significant in reducing a child’s exposure,” says Duncan. “Decreasing the number of exams, the images per exam and the dose per image are the ways we can lower children’s exposure. If you can move the dial on each of those, the savings are amazing.”

    Other methods include carefully considering the need for follow-up scans, reading scans forwarded by referring hospitals rather than automatically scheduling another CT, and determining if other imaging techniques can provide the same answer as CT.

    The key for radiologists, says Duncan, is to always keep in mind that these are children. “A 15-year-old may look fully grown, but there are vast differences between that patient and his or her 85-year-old great-grandmother,” he says. “Pediatric and adolescent patients have a lifetime ahead of them. We need to budget their radiation exposure wisely for their well-being in the future.”

    Setting the Bar for Safety

    Mallinckrodt Institute of Radiology has developed approximately 50 pediatric CT protocols, 15 to 20 of which are most commonly used. Marilyn J. Siegel, MD, professor of radiology and pediatrics, has extensive background in developing pediatric CT protocols and in working with Siemens, a developer of imaging technology, to test the manufacturer’s latest CT products. She also reviews and accredits CT protocols submitted by radiology facilities across the U.S. to the American College of Radiology.

    “Protocols are based on technology, and it is technology that has impacted our ability to reduce dosage in children,” she explains. “Since advances in CT imaging occur rapidly, it has become standard practice to review and update protocols annually to ensure we are providing our pediatric patients with the safest, highest quality scans possible.”

    Siegel cites automated tube current as the initial significant automated advance in CT technology. Tube current determines the number of electrons accelerated across the X-ray tube per unit of time. Today’s scanners are automated to select the best tube current for each patient based on variations in structure density within the scanned area of the body.

    Kilovoltage is another advance that has changed protocols for both adults and children. Kilovoltage controls the radiographic contrast of an X-ray image.

    Panda Scanner
    Above: The “Panda Scanner” at St. Louis Children’s Hospital.

    “Previously this parameter was fixed at 120. That is more than is needed for children. Now, kilovoltage can be adjusted as low as 70 and as high as 140,” says Siegel. “We can produce high quality, readable scans for pediatric patients at very low kilovoltage. Our pediatric protocols have automatic default settings for the lower kilovoltages.”

    Harrod describes the structure of protocols as branches on a tree upon which an individual CT scan is built.

    “Each branch provides particular parameters of the CT scan – for instance, the type of study needed, whether it is adult or pediatric, and the area of the body. With that information, the protocol shows default settings for elements like rotation time and beam current,” he says. “But some tweaking still can occur based on, for instance, range. An example would be scanning both the cervical spine and head to avoid having to do two separate scans, which lowers the patient’s radiation burden.”

    Siegel notes that today, low-dose CT scanning is a reality, and MIR is committed to providing the most current technology available to achieve that goal.

    “In plotting pediatric CT dosage over the years, I found that in 2000, when automated current modulation was introduced, our mean dose was 8.1. When we added automated voltage to that, our mean dose was reduced to 5.8. And when we added another new development, iterative reconstruction, the mean dose went down to 2.7,” she says. “Each of these advances has been factored into our pediatric CT protocols to produce default settings that accurately reflect the needs of our patients.”