In a new expert consensus statement in the Journal of the American College of Cardiology, the American College of Cardiology, American Society of Nuclear Cardiology, Heart Rhythm Society, North American Society for Cardiovascular Imaging, Society for Cardiovascular Angiography and Interventions, and Society for Cardiovascular Computed Tomography provided updated guidelines on best practices for improving safety when using ionizing radiation during cardiovascular imaging.
The consensus statement was made following the discovery of recent statistics that demonstrated the increasing performance frequency of ionizing radiation-based cardiovascular imaging procedures across the United States.
The consensus statement highlights the inherent cancer risk associated with high doses of medical radiation exposure, particularly lifetime doses >100 millisieverts. In addition to discussing the mechanisms of radiation-induced biologic effects, the writing committee also provided an overview of the types of dose-effect reactions to radiation, including tissue reactions (eg, cell necrosis, skin injury, bone injury, and cataracts) and stochastic effects (eg, cancer and heritable effects in offspring).
To elucidate the effect radiation exposure has on cancer risk, the committee recommended calculating the lifetime attributable cancer incidence and mortality risk. Clinicians can then obtain data on a proportion of exposed patients who may have a higher risk for a cancer diagnosis related specifically to radiation exposure.
To estimate the absorbed dose of radiation, the writing panel recommended using models that were developed by exposing instrumented “phantoms” to incident x-ray beams that replicate the beams used in diagnostic imaging and then measuring the absorbed dose at different points within the phantom. However, these models do not determine other dose-determining variables, resulting in considerable variability in absorbed estimates.
The investigators of this consensus statement also advocated for greater quality assurance when working with ionizing radiation in cardiovascular imaging. Improving quality assurance relies on verifying the performance and calibration of equipment and monitoring the metrics of exposure in patients and personnel.
Overall, there was an emphasis on proper personnel training, which “should create a culture of respect for radiation hazard and a commitment to minimize exposure and maximize protection.”
Writing Committee Members, Hirshfeld JW Jr, Ferrari VA, Bengel FM, et al. 2018 ACC/HRS/NASCI/SCAI/SCCT expert consensus document on optimal use of ionizing radiation in cardiovascular imaging-best practices for safety and effectiveness, part 2: radiological equipment operation, dose-sparing methodologies, patient and medical personnel protection [published online April 30, 2018]. J Am Coll Cardiol. doi:10.1016/j.jacc.2018.02.018