Reducing Children’s Exposure to Radiation: A Q&A With Dr. Tom Lendvay

The U.S. population faces seven times more exposure to ionizing radiation from medical procedures than it did in the early 1980s, largely due to the growth in computed tomography (CT) and nuclear medicine, according to the National Council on Radiation Protection and Measurements. Children’s hospitals are increasingly looking for ways to use lower radiation doses for diagnosis and treatment. Success has come from using new technologies and equipment specially designed for children and constantly being on the lookout for opportunities to share information and collaborate better across teams.

Why is radiation bad for children?  

Tom Lendvay, MD, urologist, Seattle Children’s: If you start receiving radiation exposure as a child, you run the risk of having a larger lifetime dose of radiation. Children exposed to radiation, especially those undergoing X-rays and CT scans to evaluate primary cancers, are also at increased risk of developing what is called a secondary malignancy, or cancer due to the DNA-damaging effects of radiation exposure as a child. These include hematologic (blood cell) cancers.

For all these reasons, we look for ways we can reduce the amount of radiation our patients are exposed to during diagnosis and treatment.

What are some of the ways kids are exposed to radiation in the hospital?

Dr. Lendvay: Children may be exposed to ionizing radiation through X-rays, CT scans, fluoroscopy (live X-rays), nuclear medicine tests and intraoperative imaging. Fortunately, children’s bodies are generally smaller and contain less fat than adults, which makes ultrasound technology a good choice much of the time. However, there are a number of conditions that require radiation imaging tests. Over the last two decades, CT scans have provided rapid, rich data and anatomic detail that surpass many other imaging modalities and has proven invaluable to the diagnosis of severe medical conditions. Thus, the use of CT scans has increased in adults and children over the last two decades.

How are you reducing radiation exposure at Seattle Children’s?

Dr. Lendvay: It’s a team effort. We are always interested in finding ways to diagnose and treat kids using less radiation. It means being alert to opportunities and acting on good ideas. Four years ago, we observed that a number of the children who were coming to the Emergency Department for presumed kidney stone pain were receiving CT scans to diagnose and localize stones, when in fact ultrasonography can give most of the diagnostic information that urologists and ED providers need to manage children. As part of our standard work efforts at Seattle Children’s, a multidisciplinary team with representatives from Nursing, the Emergency Department (ED), Urology and Radiology developed a clinical standard pathway for all children who present with kidney stone pain to the ED. This process change reduced the amount of CT scans we perform threefold over two years.

Recently, one of our urology residents, Dr. Dima Raskolnikov, leveraged his experience from our UW partner institutions in implementing evidence-based kidney stone care to help make care safer at Seattle Children’s. He queried our Radiology Department on the specific protocols used for kids with suspected kidney stones when a CT is indicated. The group calculated that there were additional reductions in radiation that could be made for a “low-dose” CT scan. This effort was communicated throughout the Radiology Department, and now there is a new standard for kidney stone “low-dose” CT scans.

Additionally, urology is applying a technique that was recently reviewed in the literature to lower the radiation exposure during fluoroscopy. Just by simply marking on the fluoroscopy machine the top-most and bottom-most position the fluoro C-arm head needs to pivot to (in order to see the whole operative field), a group in New York showed a 30% reduction in time needed for fluoroscopy.* Now the radiology technicians in the operating room who disseminate the fluoroscopy during surgeries perform a check to make sure the lowest dose settings acceptable are being used.

*Wagmaister J, Iorga M, Huang R, et al. The Two-point Technique for Fluoroscopic Guided Endoscopic Procedures in Urology–A Validation Study. Journal of Endourology. 33:691, 2019.

Is there anything new you’re excited about?

Dr. Lendvay: The most exciting effort we are instituting, in collaboration with our Radiology leadership, is the use of contrast-enhanced video ultrasonography (CEVUS). Between 1% and 3% of all children have vesicoureteral reflux, and some enable bladder infections ascending to the kidney and leading to morbid pyelonephritis. To diagnose urinary reflux, children must undergo one of two types of cystograms — either one with fluoroscopy or one with nuclear medicine. Both require ionizing radiation. CEVUS imaging uses ultrasound technology to “see” if small air bubbles are embedded within a viscous solution that is instilled into the bladder ascend the ureters. There’s no radiation involved. Some children who get CEVUS will still need the conventional cystograms to give detail about the anatomy and severity of the reflux; however, many children, especially those receiving second and postoperative cystograms, can receive the new ultrasound cystogram instead.

The use of ultrasound for evaluating urinary reflux is being used by just a handful of pediatric centers nationally, as this is a new, yet evidence-supported, technique. It requires training for our Radiology Department to perform, and education for our Urology team and referring providers to help us select patients appropriately. As Urology becomes more familiar with the imaging test, we will do more to communicate with referring provides so we can all work together to reduce the radiation exposure to our patients.

How can primary care doctors help reduce radiation exposure for their patients?

Dr. Lendvay: Always use an accredited imaging facility.

How can I reassure my patients about radiation exposure?

Dr. Lendvay: This handout shows typical radiation doses for exams performed on a 5-year old child at Seattle Children’s compared to typical doses for adults.

Dr. Lendvay practices in Urology and the multidisciplinary Kidney Stone Center. He is co-director of the Seattle Robotic Surgery Program and director of the Pediatric Urology Fellowship.