Optimization approaches key for radiation safety in children with heart disease

NEW ORLEANS — Consensus recommendations for ionizing radiation dose optimization and regulation of dose metrics are needed across multi-modality imaging procedures in children with congenital and acquired heart disease, a speaker said at the Society for Cardiovascular Angiography and Interventions Annual Meeting.

Optimization of appropriate approaches to less radiation risks for children with heart disease was the topic of a session at the meeting and of a scientific position statement published this week in JACC: Cardiovascular Imaging.

Risks of exposure

It is estimated that 1 million U.S. children are living with congenital heart disease. An additional 1 in every 100,000 U.S. children and adolescents develop forms of acquired heart disease each year. The lifelong care of children with congenital and acquired heart disease is complex, and often requires procedures that use ionizing radiation, including cardiac CT scans, nuclear medicine studies, fluoroscopically guided diagnostic and interventional catheterization, and electrophysiology procedures.

The average number of exposures to ionizing radiation per patient has increased substantially over the past two decades, according to the statement. Doses associated with pediatric cardiac catheterization, for example, are generally low, typically ranging from 1 mSv to 20 mSv, although doses can be as high 100 mSv, Kevin D. Hill, MD, from the division of pediatric cardiology at Duke University Medical Center, said during a presentation at SCAI 2017.

Across several studies, catheterization is the most significant source of cumulative radiation exposure in children with heart disease, he said. In comparison, annual background radiation exposure to a person in the United States is about 3 mSv per year, he said.

Exposure to ionizing radiation is associated with potential risks, from tissue reactions to stochastic effects.

“There are good data to support increased lifetime cancer risk for exposures above 50 mSv. But the data are less clear for low-dose exposures below 20 mSv,” Hill said.

Moreover, it has been established that cancer risk increases with cumulative exposure, and even low doses are associated with some risk, he said. Risk is particularly increased in neonates compared with older children and in women compared with men.

Consensus recommendations

The new position paper, Radiation Safety in Children with Congenital and Acquired Heart Disease: A Scientific Position Statement on Multimodality Dose Optimization from the Image Gently Alliance, provides cardiologists, radiologists, pediatricians, internal medicine physicians and other health care professionals with guidance for the treatment of pediatric patients with congenital and acquired heart disease. The goal of the Image Gently Alliance is to improve safe, effective imaging care of children around the world.

Recommendations include strategies for dose optimization during:

Cardiac CT, with approaches that can be implemented during patient preparation, as well as scanner-based approaches.

Nuclear cardiology procedures, with procedural approaches and guidelines for determining administered activity in children.

Fluoroscopically guided procedures including cardiac catheterization and electrophysiology procedures, with recommendations focused on hardware features, software configuration and operator-dependent techniques.

Other strategies to improve care include a patient-centered approach to imaging, emphasizing education and informed decision making, and programmatic approaches to ensure appropriate dose monitoring.

When set up correctly and used appropriately, new equipment can yield dose optimization, according to Hill. He referenced a study that evaluated effective radiation doses with the latest-generation (release date: 2011-2014) imaging equipment from GE Healthcare, Philips Healthcare, Siemens Healthcare and Toshiba compared with an older system released in 2004, and found lower doses with the newer devices.

Another important factor is to choose child-size settings. Adult settings in a neonate are associated with a many-fold increase in radiation dose, Hill said.

Other operator techniques that can make a difference, Hill said, include lowering the receptor; collimation; magnification; removing extraneous objects from the imaging field of view; and removing the anti-scatter grid in small children.

“These approaches are comprehensive, covering the spectrum of hardware and software features and configuration, as well as operator-dependent approaches to imaging. If broadly implemented by programs caring for children with congenital and acquired heart disease, these recommendations could facilitate significant population-level reductions in cumulative ionizing radiation exposure while concomitantly ensuring high-quality imaging that does not compromise diagnostic integrity or procedural safety,” the statement reads.

Efforts to develop program-wide dose-monitoring procedures are also recommended.

A full description of the consensus recommendations is available in the JACC: Cardiovascular Imaging publication.

“Our goal is to focus on approaches that, when properly implemented, will lessen radiation risks for children with heart disease while still allowing the imaging procedures to be effective,” Hill said in a press release. – by Katie Kalvaitis

References:

Hill KD. General Principles of Radiation Reduction. Presented at: Society for Cardiovascular Angiography and Interventions Annual Meeting; May 10-13, 2017; New Orleans.

Hill KD, et al. JACC Cardiovasc Imaging. 2017;doi:10.1016/j.jcmg.2017.04.003.

The Image Gently Alliance. www.imagegently.org.

Disclosure: Hill reports no relevant financial disclosures. See the full position statement for a list of the authors’ relevant financial disclosures.